?Hydrogen sulfide is an impurity in natural gas that must be removed. One common removal

The reaction between reactant A (blue spheres) and reactant B (red spheres) is shown in the following diagram: Based on this diagram, which equation best describes the reaction? [Section 3.1 ] (a) \(\mathrm{A}_{2}+\mathrm{B} \longrightarrow \mathrm{A}_{2} \mathrm{~B}\) (b) \(\mathrm{A}_{2}+4 \mathrm{~B} \longrightarrow 2 \mathrm{AB}_{2}\) (c) \(2 \mathrm{~A}+\mathrm{B}_{4} \longrightarrow 2 \mathrm{AB}_{2}\) (d) \(\mathrm{A}+\mathrm{B}_{2} \longrightarrow \mathrm{AB}_{2}\) Text Transcription: A_2+B longrightarrow A_2 B A_2+4 B longrightarrow 2AB_2 2 A+B_4 longrightarrow 2 AB_2 A+B_2 longrightarrow AB_2

The following diagram shows the combination reaction between hydrogen, H2, and carbon monoxide, CO, to produce methanol, CH3OH (white spheres are H, black spheres are C, red spheres are O). The correct number of CO molecules involved in this reaction is not shown. [Section 3.1] (a) Determine the number of CO molecules that should be shown in the left (reactants) box. (b) Write a balanced chemical equation for the reaction.

The following diagram represents the collection of elements formed by a decomposition reaction. (a) If the blue spheres represent N atoms and the red ones represent O atoms, what was the empirical formula of the original compound? (b) Could you draw a diagram representing the molecules of the compound that had been decomposed? Why or why not? [Section 3.2 ]

The following diagram represents the collection of CO2 and H2O molecules formed by complete combustion of a hydrocarbon. What is the empirical formula of the hydrocarbon? [Section 3.2]

Glycine, an amino acid used by organisms to make proteins, is represented by the following molecular model. (a) Write its molecular formula. (b) Determine its molar mass. (c) Calculate how many moles of glycine are in a 100.0-g sample of glycine. (d) Calculate the percent nitrogen by mass in glycine. [Sections 3.3 and 3.5]

The following diagram represents a high-temperature reaction between CH4 and H2O. Based on this reaction, find how many moles of each product can be obtained starting with 4.0 mol CH4. [Section 3.6]

Nitrogen (N2) and hydrogen (H2) react to form ammonia (NH3). Consider the mixture of N2 and H2 shown in the accompanying diagram. The blue spheres represent N, and the white ones represent H. (a) Write the balanced chemical equation for the reaction. (b) What is the limiting reactant? (c) How many molecules of ammonia can be made, assuming the reaction goes to completion, based on the diagram? (d) Are any reactant molecules left over, based on the diagram? If so, how many of which type are left over? [Section 3.7]

Nitrogen monoxide and oxygen react to form nitrogen dioxide. Consider the mixture of NO and O2 shown in the accompanying diagram. The blue spheres represent N, and the red ones represent O. (a) How many molecules of NO2 can be formed, assuming the reaction goes to completion? (b) What is the limiting reactant? (c) If the actual yield of the reaction was 75% instead of 100%, how many molecules of each kind would be present after the reaction was over?

Write “true” or “false” for each statement. (a) We balance chemical equations as we do because energy must be conserved. (b) If the reaction \(2 \mathrm{O}_{3}(g) \rightarrow 3 \mathrm{O}_{2}(g)\) goes to completion and all O3 is converted to O2, then the mass of O3 at the beginning of the reaction must be the same as the mass of O2 at the end of the reaction. (c) You can balance the “water-splitting” reaction /(\mathrm{H}_{2} \mathrm{O}(l) \rightarrow \mathrm{H}_{2}(g)+\mathrm{O}_{2}(g)\) by writing it this way: \(\mathrm{H}_{2} \mathrm{O}_{2}(l) \rightarrow \mathrm{H}_{2}(g)+\mathrm{O}_{2}(g)\). Text Transcription: 2O_3(g) rightarrow 3O_2(g) H_2O(l) rightarrow H_2(g)+O_2(g)

A key step in balancing chemical equations is correctly identifying the formulas of the reactants and products. For example, consider the reaction between calcium oxide, CaO(s), and H2O(l) to form aqueous calcium hydroxide. (a) Write a balanced chemical equation for this combination reaction, having correctly identified the product as Ca(OH)2(aq). (b) Is it possible to balance the equation if you incorrectly identify the product as CaOH(aq), and if so, what is the equation?

Balance the following equations: (a) \(\mathrm{CO}(g)+\mathrm{O}_{2}(g) \longrightarrow \mathrm{CO}_{2}(g)\) (b) \(\mathrm{N}_{2} \mathrm{O}_{5}(g)+\mathrm{H}_{2} \mathrm{O}(l) \longrightarrow \mathrm{HNO}_{3}(a q)\) (c) \(\mathrm{CH}_{4}(g)+\mathrm{Cl}_{2}(g) \longrightarrow \mathrm{CCl}_{4}(l)+\mathrm{HCl}(g)\) (d) \(\mathrm{Zn}(\mathrm{OH})_{2}(s)+\mathrm{HNO}_{3}(a q) \longrightarrow \mathrm{Zn}\left(\mathrm{NO}_{3}\right)_{2}(a q)+\mathrm{H}_{2} \mathrm{O}(l)\) Text Transcription: CO(g)+O_2(g) longrightarrow CO_2(g) N_2O_5(g)+H_2O(l) longrightarrow HNO_3(aq) CH_4(g)+Cl_2(g) longrightarrow CCl_4(l)+HCl(g) Zn(OH)_2(s)+HNO_3(aq) longrightarrow Zn(NO_3)_2(aq)+H_2O(l)

Balance the following equations: (a) \(\mathrm{Li}(s)+\mathrm{N}_{2}(g) \longrightarrow \mathrm{Li}_{3} \mathrm{~N}(s)\) (b) \(\mathrm{TiCl}_{4}(l)+\mathrm{H}_{2} \mathrm{O}(l) \longrightarrow \mathrm{TiO}_{2}(s)+\mathrm{HCl}(a q)\) (c) \(\mathrm{NH}_{4} \mathrm{NO}_{3}(s) \longrightarrow \mathrm{N}_{2}(g)+\mathrm{O}_{2}(g)+\mathrm{H}_{2} \mathrm{O}(g)\) (d) \(\mathrm{AlCl}_{3}(s)+\mathrm{Ca}_{3} \mathrm{~N}_{2}(s) \longrightarrow \mathrm{AlN}(s)+\mathrm{CaCl}_{2}(s)\) Text Transcription: Li(s)+N_2(g) longrightarrow Li_3N(s) TiCl_4(l)+H_2O(l) longrightarrow TiO_2(s)+HCl(aq) NH_4NO_3(s) longrightarrow N_2(g)+O_2(g)+H_2O(g) AlCl_3(s)+Ca_3N_2(s) longrightarrow AlN(s)+CaCl_2(s)

Balance the following equations: (a) \(\mathrm{Al}_{4} \mathrm{C}_{3}(s)+\mathrm{H}_{2} \mathrm{O}(l) \longrightarrow \mathrm{Al}(\mathrm{OH})_{3}(s)+\mathrm{CH}_{4}(g)\) (b) \(\mathrm{C}_{5} \mathrm{H}_{10} \mathrm{O}_{2}(l)+\mathrm{O}_{2}(g) \longrightarrow \mathrm{CO}_{2}(g)+\mathrm{H}_{2} \mathrm{O}(g)\) (c) \(\mathrm{Fe}(\mathrm{OH})_{3}(s)+\mathrm{H}_{2} \mathrm{SO}_{4}(a q) \longrightarrow \mathrm{Fe}_{2}\left(\mathrm{SO}_{4}\right)_{3}(a q)+\mathrm{H}_{2} \mathrm{O}(l)\) (d) \(\mathrm{Mg}_{3} \mathrm{~N}_{2}(s)+\mathrm{H}_{2} \mathrm{SO}_{4}(a q) \longrightarrow \mathrm{MgSO}_{4}(a q)+\left(\mathrm{NH}_{4}\right)_{2} \mathrm{SO}_{4}(a q)\) Text Transcription: Al_4C_3(s)+H_2O(l) longrightarrow Al(OH)_3(s)+CH_4(g) C_5H_10O_2(l)+O_2(g) longrightarrow CO_2(g)+H_2O(g) Fe(OH)_3(s)+H_2SO_4(aq) longrightarrow Fe_2(SO_4)_3(aq)+H_2O(l) Mg_3N_2(s)+H_2SO_4(aq) longrightarrow MgSO_4(aq)+(NH_4)_2SO_4(aq)

Balance the following equations: (a) \(\mathrm{Ca}_{3} \mathrm{P}_{2}(s)+\mathrm{H}_{2} \mathrm{O}(l) \longrightarrow \mathrm{Ca}(\mathrm{OH})_{2}(a q)+\mathrm{PH}_{3}(g)\) (b) \(\mathrm{Al}(\mathrm{OH})_{3}(s)+\mathrm{H}_{2} \mathrm{SO}_{4}(a q) \longrightarrow \mathrm{Al}_{2}\left(\mathrm{SO}_{4}\right)_{3}(a q)+\mathrm{H}_{2} \mathrm{O}(l)\) (c) \(\mathrm{AgNO}_{3}(a q)+\mathrm{Na}_{2} \mathrm{CO}_{3}(a q) \longrightarrow \mathrm{Ag}_{2} \mathrm{CO}_{3}(s)+\mathrm{NaNO}_{3}(a q)\) (d) \(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{NH}_{2}(g)+\mathrm{O}_{2}(g) \longrightarrow \mathrm{CO}_{2}(g)+\mathrm{H}_{2} \mathrm{O}(g)+\mathrm{N}_{2}(g)\) Text Transcription: Ca_3P_2(s)+H_2O(l) longrightarrow Ca(OH)_2(aq)+PH_3(g) Al(OH)_3(s)+H_2SO_4(aq) longrightarrow Al_2(SO_4)_3(aq)+H_2O(l) AgNO_3(aq)+Na_2CO_3(aq) longrightarrow Ag_2CO_3(s)+NaNO_3(aq) C_2H_5NH_2(g)+O_2(g) longrightarrow CO_2(g)+H_2O(g)+N_2(g)

Write balanced chemical equations corresponding to each of the following descriptions: (a) Solid calcium carbide, CaC2, reacts with water to form an aqueous solution of calcium hydroxide and acetylene gas, C2H2. (b) When solid potassium chlorate is heated, it decomposes to form solid potassium chloride and oxygen gas. (c) Solid zinc metal reacts with sulfuric acid to form hydrogen gas and an aqueous solution of zinc sulfate. (d) When liquid phosphorus trichloride is added to water, it reacts to form aqueous phosphorous acid, H3PO3(aq), and aqueous hydrochloric acid. (e) When hydrogen sulfide gas is passed over solid hot iron(III) hydroxide, the resulting reaction produces solid iron(III) sulfide and gaseous water.

Write balanced chemical equations to correspond to each of the following descriptions: (a) When sulfur trioxide gas reacts with water, a solution of sulfuric acid forms. (b) Boron sulfide, B2S3(s), reacts violently with water to form dissolved boric acid, H3BO3, and hydrogen sulfide gas. (c) Phosphine, PH3(g), combusts in oxygen gas to form water vapor and solid tetraphosphorus decaoxide. (d) When solid mercury(II) nitrate is heated, it decomposes to form solid mercury( II) oxide, gaseous nitrogen dioxide, and oxygen. (e) Copper metal reacts with hot concentrated sulfuric acid solution to form aqueous copper(II) sulfate, sulfur dioxide gas, and water.

(a) When the metallic element sodium combines with the nonmetallic element bromine, Br2(l), what is the chemical formula of the product? (b) Is the product a solid, liquid, or gas at room temperature? (c) In the balanced chemical equation for this reaction, what is the coefficient in front of the product if the coefficient in front of Br2(l) is 1?

(a) When a compound containing C, H, and O is completely combusted in air, what reactant besides the hydrocarbon is involved in the reaction? (b) What products form in this reaction? (c) What is the sum of the coefficients in the balanced chemical equation for the combustion of one mole of acetone, C3H6O(l), in air?

Write a balanced chemical equation for the reaction that occurs when (a) Mg(s) reacts with Cl2(g); (b) barium carbonate decomposes into barium oxide and carbon dioxide gas when heated; (c) the hydrocarbon styrene, C8H8(l), is combusted in air; (d) dimethylether, CH3OCH3(g), is combusted in air.

Write a balanced chemical equation for the reaction that occurs when (a) titanium metal reacts with O2(g); (b) silver(I) oxide decomposes into silver metal and oxygen gas when heated; (c) propanol, C3H7OH(l) burns in air; (d) methyl tert-butyl ether, C5H12O(l), burns in air.

Balance the following equations and indicate whether they are combination, decomposition, or combustion reactions: (a) \(\mathrm{C}_{3} \mathrm{H}_{6}(g)+\mathrm{O}_{2}(g) \longrightarrow \mathrm{CO}_{2}(g)+\mathrm{H}_{2} \mathrm{O}(g)\) (b) \(\mathrm{NH}_{4} \mathrm{NO}_{3}(s) \longrightarrow \mathrm{N}_{2} \mathrm{O}(g)+\mathrm{H}_{2} \mathrm{O}(g)\) (c) \(\mathrm{C}_{5} \mathrm{H}_{6} \mathrm{O}(l)+\mathrm{O}_{2}(g) \longrightarrow \mathrm{CO}_{2}(g)+\mathrm{H}_{2} \mathrm{O}(g)\) (d) \(\mathrm{N}_{2}(g)+\mathrm{H}_{2}(g) \longrightarrow \mathrm{NH}_{3}(g)/) (e) \(\mathrm{K}_{2} \mathrm{O}(s)+\mathrm{H}_{2} \mathrm{O}(l) \longrightarrow \mathrm{KOH}(a q)\) Text Transcription: C_3H_6(g)+O_2(g) longrightarrow CO_2(g)+H_2O(g) NH_4NO_3(s) longrightarrow N_2O(g)+H_2O(g) C_5H_6O(l)+O_2(g) longrightarrow CO_2(g)+H_2O(g) N_2(g)+H_2(g) longrightarrow NH_3(g) K_2O(s)+H_2O(l) longrightarrow KOH(aq)

Balance the following equations and indicate whether they are combination, decomposition, or combustion reactions: (a) \(\mathrm{PbCO}_{3}(s) \longrightarrow \mathrm{PbO}(s)+\mathrm{CO}_{2}(g)\) (b) \(\mathrm{C}_{2} \mathrm{H}_{4}(g)+\mathrm{O}_{2}(g) \longrightarrow \mathrm{CO}_{2}(g)+\mathrm{H}_{2} \mathrm{O}(g)\) (c) \(\mathrm{Mg}(s)+\mathrm{N}_{2}(g) \longrightarrow \mathrm{Mg}_{3} \mathrm{~N}_{2}(s)\) (d) \(\mathrm{C}_{7} \mathrm{H}_{8} \mathrm{O}_{2}(l)+\mathrm{O}_{2}(g) \longrightarrow \mathrm{CO}_{2}(g)+\mathrm{H}_{2} \mathrm{O}(g)/) (e) \(\mathrm{Al}(s)+\mathrm{Cl}_{2}(g) \longrightarrow \mathrm{AlCl}_{3}(s)\) Text Transcription: PbCO_3(s) longrightarrow PbO(s)+CO_2(g) C_2H_4(g)+O_2(g) longrightarrow CO_2(g)+H_2O(g) Mg(s)+N_2(g) longrightarrow Mg_3N_2(s) C_7H_8O_2(l)+O_2(g) longrightarrow CO_2(g)+H_2O(g) Al(s)+Cl_2(g) longrightarrow AlCl_3(s)

Determine the formula weights of each of the following compounds: (a) nitric acid, HNO3; (b) KMnO4; (c) Ca3(PO4)2; (d) quartz, SiO2; (e) gallium sulfide, (f) chromium(III) sulfate, (g) phosphorus trichloride.

Determine the formula weights of each of the following compounds: (a) nitrous oxide, N2O, known as laughing gas and used as an anesthetic in dentistry; (b) benzoic acid; C6H5COOH, a substance used as a food preservative; (c) Mg(OH)2, the active ingredient in milk of magnesia; (d) urea, (NH2)2CO, a compound used as a nitrogen fertilizer; (e) isopentyl acetate, CH3CO2C5H11, responsible for the odor of bananas.

Calculate the percentage by mass of oxygen in the following compounds: (a) morphine, C17H19NO3; (b) codeine, C18H21NO3 ; (c) cocaine, C17H21NO4; (d) tetracycline, C22H24N2O8; (e) digitoxin, C41H64O13; (f) vancomycin, C66H75Cl2N9O24.

Calculate the percentage by mass of the indicated element in the following compounds: (a) carbon in acetylene, C2H2, a gas used in welding; (b) hydrogen in ascorbic acid, HC6H7O6, also known as vitamin C; (c) hydrogen in ammonium sulfate, (NH4)2SO4, a substance used as a nitrogen fertilizer; (d) platinum in PtCl2(NH3)2, a chemotherapy agent called cisplatin; (e) oxygen in the female sex hormone estradiol, C18H24O2; (f) carbon in capsaicin, C18H27NO3, the compound that gives the hot taste to chili peppers.

Based on the following structural formulas, calculate the percentage of carbon by mass present in each compound:

Calculate the percentage of carbon by mass in each of the compounds represented by the following models:

(a) Write “true” or “false” for each statement. (a) A mole of horses contains a mole of horse legs (b) A mole of water has a mass of 18.0 g. (c) The mass of 1 molecule of water is 18.0 g. (d) A mole of NaCl(s) contains 2 moles of ions.

(a) What is the mass, in grams, of one mole of 12C? (b) How many carbon atoms are present in one mole of 12C?

Without doing any detailed calculations (but using a periodic table to give atomic weights), rank the following samples in order of increasing numbers of atoms: 0.50 mol H2O, 23 g Na, 6.0 1023 N2 molecules.

Write a structural formula for the most stable chair conformation of each of the following compounds: (a) cis-1-Isopropyl-3-methylcyclohexane (b) trans-1-Isopropyl-3-methylcyclohexane (c) cis-1-tert-Butyl-4-ethylcyclohexane (d) cis-1,1,3,4-Tetramethylcyclohexane (e)

What is the mass, in kilograms, of an Avogadro’s number of people, if the average mass of a person is 160 lb? How does this compare with the mass of Earth, 5.98 1024 kg?

If Avogadro’s number of pennies is divided equally among the 321 million men, women, and children in the United States, how many dollars would each receive? How does this compare with the gross domestic product (GDP) of the United States, which was $17.419 trillion in 2015? (The GDP is the total market value of the nation’s goods and services.)

Calculate the following quantities: (a) mass, in grams, of 0.105 mol sucrose (C12H22O11) (b) moles of Zn(NO3)2 in 143.50 g of this substance (c) number of molecules in 1.0 10-6 mol CH3CH2OH (d) number of N atoms in 0.410 mol NH3

Calculate the following quantities: (a) mass, in grams, of 1.50 10-2 mol CdS (b) number of moles of NH4Cl in 86.6 g of this substance (c) number of molecules in 8.447 10-2 mol C6H6 (d) number of O atoms in 6.25 10-3 mol Al(NO3)3

(a) What is the mass, in grams, of 2.50 10-3 mol of ammonium phosphate? (b) How many moles of chloride ions are in 0.2550 g of aluminum chloride? (c) What is the mass, in grams, of 7.70 1020 molecules of caffeine, C8H10N4O2? (d) What is the molar mass of cholesterol if 0.00105 mol has a mass of 0.406 g?

(a) What is the mass, in grams, of 1.223 mol of iron(III) sulfate? (b) How many moles of ammonium ions are in 6.955 g of ammonium carbonate? (c) What is the mass, in grams, of 1.50 1021 molecules of aspirin, C9H8O4? (d) What is the molar mass of diazepam (Valium®) if 0.05570 mol has a mass of 15.86 g?

The molecular formula of allicin, the compound responsible for the characteristic smell of garlic, is C6H10OS2. (a) What is the molar mass of allicin? (b) How many moles of allicin are present in 5.00 mg of this substance? (c) How many molecules of allicin are in 5.00 mg of this substance? (d) How many S atoms are present in 5.00 mg of allicin?

The molecular formula of aspartame, the artificial sweetener marketed as NutraSweet®, is C14H18N2O5. (a) What is the molar mass of aspartame? (b) How many moles of aspartame are present in 1.00 mg of aspartame? (c) How many molecules of aspartame are present in 1.00 mg of aspartame? (d) How many hydrogen atoms are present in 1.00 mg of aspartame?

A sample of glucose, C6H12O6, contains 1.250 1021 carbon atoms. (a) How many atoms of hydrogen does it contain? (b) How many molecules of glucose does it contain? (c) How many moles of glucose does it contain? (d) What is the mass of this sample in grams?

A sample of the male sex hormone testosterone, C19H28O2, contains 3.88 1021 hydrogen atoms. (a) How many atoms of carbon does it contain? (b) How many molecules of testosterone does it contain? (c) How many moles of testosterone does it contain? (d) What is the mass of this sample in grams?

The allowable concentration level of vinyl chloride, C2H3Cl, in the atmosphere in a chemical plant is 2.0 10-6 g/L. How many moles of vinyl chloride in each liter does this represent?How many molecules per liter?

At least 25 g of tetrahydrocannabinol (THC), the active ingredient in marijuana, is required to produce intoxication. The molecular formula of THC is C21H30O2. How many moles of THC does this 25 g represent? How many molecules?

Give the empirical formula of each of the following compounds if a sample contains (a) 0.0130 mol C, 0.0390 mol H, and 0.0065 mol O; (b) 11.66 g iron and 5.01 g oxygen; (c) 40.0% C, 6.7% H, and 53.3% O by mass.

Determine the empirical formula of each of the following compounds if a sample contains (a) 0.104 mol K, 0.052 mol C, and 0.156 mol O; (b) 5.28 g Sn and 3.37 g F; (c) 87.5% N and 12.5% H by mass.

Determine the empirical formulas of the compounds with the following compositions by mass: (a) 10.4% C, 27.8% S, and 61.7% Cl (b) 21.7% C, 9.6% O, and 68.7% F (c) 32.79% Na, 13.02% Al, and the remainder F

Determine the empirical formulas of the compounds with the following compositions by mass: (a) 55.3% K, 14.6% P, and 30.1% O (b) 24.5% Na, 14.9% Si, and 60.6% F (c) 62.1% C, 5.21% H, 12.1% N, and the remainder O

A compound whose empirical formula is XF3 consists of 65% F by mass. What is the atomic mass of X?

The compound XCl4 contains 75.0% Cl by mass. What is element X?

What is the molecular formula of each of the following compounds? (a) empirical formula CH2, molar mass = 84.0 g/mol (b) empirical formula NH2Cl, molar mass = 51.5 g/mol

What is the molecular formula of each of the following compounds? (a) empirical formula HCO2, molar mass = 90.0 g/mol (b) empirical formula C2H4O, molar mass = 88.0 g/mol

Determine the empirical and molecular formulas of each of the following substances: (a) Styrene, a compound used to make Styrofoam® cups and insulation, contains 92.3% C and 7.7% H by mass and has a molar mass of 104 g/mol. (b) Caffeine, a stimulant found in coffee, contains 49.5% C, 5.15% H, 28.9% N, and 16.5% O by mass and has a molar mass of 195 g/mol. (c) Monosodium glutamate (MSG), a flavor enhancer in certain foods, contains 35.51% C, 4.77% H, 37.85% O, 8.29% N, and 13.60% Na, and has a molar mass of 169 g/mol.

Determine the empirical and molecular formulas of each of the following substances: (a) Ibuprofen, a headache remedy, contains 75.69% C, 8.80% H, and 15.51% O by mass and has a molar mass of 206 g/mol. (b) Cadaverine, a foul-smelling substance produced by the action of bacteria on meat, contains 58.55% C, 13.81% H, and 27.40% N by mass; its molar mass is 102.2 g/mol. (c) Epinephrine (adrenaline), a hormone secreted into the bloodstream in times of danger or stress, contains 59.0% C, 7.1% H, 26.2% O, and 7.7% N by mass; its molar mass is about 180 amu.

(a) Combustion analysis of toluene, a common organic solvent, gives 5.86 mg of CO2 and 1.37 mg of H2O. If the compound contains only carbon and hydrogen, what is its empirical formula? (b) Menthol, the substance we can smell in mentholated cough drops, is composed of C, H, and O. A 0.1005-g sample of menthol is combusted, producing 0.2829 g of CO2 and 0.1159 g of H2O. What is the empirical formula for menthol? If menthol has a molar mass of 156 g/mol, what is its molecular formula?

(a) The characteristic odor of pineapple is due to ethyl butyrate, a compound containing carbon, hydrogen, and oxygen. Combustion of 2.78 mg of ethyl butyrate produces 6.32 mg of CO2 and 2.58 mg of H2O. What is the empirical formula of the compound? (b) Nicotine, a component of tobacco, is composed of C, H, and N. A 5.250-mg sample of nicotine was combusted, producing 14.242 mg of CO2 and 4.083 mg of H2O. What is the empirical formula for nicotine? If nicotine has a molar mass of 160 ± 5 g/mol, what is its molecular formula?

Valproic acid, used to treat seizures and bipolar disorder, is composed of C, H, and O. A 0.165-g sample is combusted to produce 0.166 g of water and 0.403 g of carbon dioxide. What is the empirical formula for valproic acid? If the molar mass is 144 g/mol, what is the molecular formula?

Propenoic acid, C3H4O2, is a reactive organic liquid that is used in the manufacturing of plastics, coatings, and adhesives. An unlabeled container is thought to contain this liquid. A 0.275-g sample of the liquid is combusted to produce 0.102 g of water and 0.374 g carbon dioxide. Is the unknown liquid propenoic acid? Support your reasoning with calculations.

Washing soda, a compound used to prepare hard water for washing laundry, is a hydrate, which means that a certain number of water molecules are included in the solid structure. Its formula can be written as Na2CO3 ????H2O, where x is the number of moles of H2O per mole of Na2CO3. When a 2.558-g sample of washing soda is heated at 125 °C, all the water of hydration is lost, leaving 0.948 g of Na2CO3. What is the value of ?????

Epsom salts, a strong laxative used in veterinary medicine, is a hydrate, which means that a certain number of water molecules are included in the solid structure. The formula for Epsom salts can be written as MgSO4 ????H2O, where x indicates the number of moles of H2O per mole of MgSO4. When 5.061 g of this hydrate is heated to 250 °C, all the water of hydration is lost, leaving 2.472 g of MgSO4. What is the value of ?????

Hydrofluoric acid, HF(aq), cannot be stored in glass bottles because compounds called silicates in the glass are attacked by the HF(aq). Sodium silicate (Na2SiO3), for example, reacts as follows: \(\mathrm{Na}_{2} \mathrm{SiO}_{3}(s)+8 \mathrm{HF}(a q) \longrightarrow \mathrm{H}_{2} \mathrm{SiF}_{6}(a q)+2 \mathrm{NaF}(a q)+3 \mathrm{H}_{2} \mathrm{O}(l)\) (a) How many moles of HF are needed to react with 0.300 mol of Na2SiO3? (b) How many grams of NaF form when 0.500 mol of HF reacts with excess Na2SiO3? (c) How many grams of Na2SiO3 can react with 0.800 g of HF? Text Transcription: Na_2SiO_3(s)+8HF(aq) longrightarrow H_2SiF_6(aq)+2NaF(aq)+3H_2O(l)

The reaction between potassium superoxide, KO2, and CO2, \(4 \mathrm{KO}_{2}+2 \mathrm{CO}_{2} \longrightarrow 2 \mathrm{~K}_{2} \mathrm{CO}_{3}+3 \mathrm{O}_{2}\) is used as a source of O2 and absorber of CO2 in self contained breathing equipment used by rescue workers. (a) How many moles of O2 are produced when 0.400 mol of KO2 reacts in this fashion? (b) How many grams of KO2 are needed to form 7.50 g of O2? (c) How many grams of CO2 are used when 7.50 g of O2 are produced? Text Transcription: 4KO_2+2CO_2 longrightarrow 2K_2CO_3+3O_2

Several brands of antacids use Al(OH)3 to react with stomach acid, which contains primarily HCl: \(\mathrm{Al}(\mathrm{OH})_{3}(s)+\mathrm{HCl}(a q) \longrightarrow \mathrm{AlCl}_{3}(a q)+\mathrm{H}_{2} \mathrm{O}(l)/) (a) Balance this equation. (b) Calculate the number of grams of HCl that can react with 0.500 g of Al(OH)3. (c) Calculate the number of grams of AlCl3 and the number of grams of H2O formed when 0.500 g of Al(OH)3 reacts. (d) Show that your calculations in parts (b) and (c) are consistent with the law of conservation of mass. Text Transcription: Al(OH)_3(s)+HCl(aq) longrightarrow AlCl_3(aq)+H_2O(l)

An iron ore sample contains Fe2O3 together with other substances. Reaction of the ore with CO produces iron metal: \(\mathrm{Fe}_{2} \mathrm{O}_{3}(s)+\mathrm{CO}(g) \longrightarrow \mathrm{Fe}(s)+\mathrm{CO}_{2}(g)/) (a) Balance this equation. (b) Calculate the number of grams of CO that can react with 0.350 kg of Fe2O3. (c) Calculate the number of grams of Fe and the number of grams of CO2 formed when 0.350 kg of Fe2O3 reacts. (d) Show that your calculations in parts (b) and (c) are consistent with the law of conservation of mass. Text Transcription: Fe_2O_3(s)+CO(g) longrightarrow Fe(s)+CO_2(g)

Aluminum sulfide reacts with water to form aluminum hydroxide and hydrogen sulfide. (a) Write the balanced chemical equation for this reaction. (b) How many grams of aluminum hydroxide are obtained from 14.2 g of aluminum sulfide?

Calcium hydride reacts with water to form calcium hydroxide and hydrogen gas. (a) Write a balanced chemical equation for the reaction. (b) How many grams of calcium hydride are needed to form 4.500 g of hydrogen?

Automotive air bags inflate when sodium azide, NaN3, rapidly decomposes to its component elements: \(2 \mathrm{NaN}_{3}(s) \longrightarrow 2 \mathrm{Na}(s)+3 \mathrm{~N}_{2}(g)\) (a) How many moles of N2 are produced by the decomposition of 1.50 mol of NaN3? (b) How many grams of NaN3 are required to form 10.0 g of nitrogen gas? (c) How many grams of NaN3 are required to produce 10.0 ft3 of nitrogen gas, about the size of an automotive air bag, if the gas has a density of 1.25 g/L? Text Transcription: 2NaN_3(s) longrightarrow 2Na(s)+3N_2(g)

The complete combustion of octane, C8H18, a component of gasoline, proceeds as follows: \(2 \mathrm{C}_{8} \mathrm{H}_{18}(l)+25 \mathrm{O}_{2}(g) \longrightarrow 16 \mathrm{CO}_{2}(g)+18 \mathrm{H}_{2} \mathrm{O}(g)\) (a) How many moles of O2 are needed to burn 1.50 mol of C8H18? (b) How many grams of O2 are needed to burn 10.0 g of C8H18? (c) Octane has a density of 0.692 g/mL at 20 °C. How many grams of O2 are required to burn 15.0 gal of C8H18 (the capacity of an average fuel tank)? (d) How many grams of CO2are produced when 15.0 gal of C8H18 are combusted? Text Transcription: 2C_8H_8(l)+25O_2(g) longrightarrow 16CO_2(g)+18H_2O(g)

A piece of aluminum foil 1.00 cm2 and 0.550-mm thick is allowed to react with bromine to form aluminum bromide. (a) How many moles of aluminum were used? (The density of aluminum is 2.699 g/cm3.) (b) How many grams of aluminum bromide form, assuming the aluminum reacts completely?

Detonation of nitroglycerin proceeds as follows: \(4 \mathrm{C}_{3} \mathrm{H}_{5} \mathrm{~N}_{3} \mathrm{O}_{9}(l) \longrightarrow\) \(12 \mathrm{CO}_{2}(g)+6 \mathrm{~N}_{2}(g)+\mathrm{O}_{2}(g)+10 \mathrm{H}_{2} \mathrm{O}(g)\) (a) If a sample containing 2.00 mL of nitroglycerin (density = 1.592 g/mL) is detonated, how many moles of gas are produced? (b) If each mole of gas occupies 55 L under the conditions of the explosion, how many liters of gas are produced? (c) How many grams of N2 are produced in the detonation? Text Transcription: 4C_3H_5N_3O_9(l) longrightarrow 12CO_2(g)+6N_2(g)+O_2(g)+10H_2O(g)

The combustion of one mole of liquid ethanol, CH3CH2OH, produces 1367 kJ of heat. Calculate how much heat is produced when 235.0 g of ethanol are combusted.

The combustion of one mole of liquid octane, CH3(CH2)6CH3, produces 5470 kJ of heat. Calculate how much heat is produced if 1.000 gallon of octane is combusted. See Exercise 3.68 for necessary information about octane.

(a) Define the terms limiting reactant and excess reactant. (b) Why are the amounts of products formed in a reaction determined only by the amount of the limiting reactant? (c) Why should you base your choice of which compound is the limiting reactant on its number of initial moles, not on its initial mass in grams?

Define the terms theoretical yield, actual yield, and percent yield. (b) Why is the actual yield in a reaction almost always less than the theoretical yield? (c) Can a reaction ever have 110% actual yield?

Consider the mixture of ethanol, C2H5OH, and O2 shown in the accompanying diagram. (a) Write a balanced equation for the combustion reaction that occurs between ethanol and oxygen. (b) Which reactant is the limiting reactant? (c) How many molecules of CO2, H2O, C2H5OH, and O2 will be present if the reaction goes to completion?

Consider the mixture of propane, C3H8, and O2 shown here. (a) Write a balanced equation for the combustion reaction that occurs between propane and oxygen. (b) Which reactant is the limiting reactant? (c) How many molecules of CO2, H2O, C3H8, and O2 will be present if the reaction goes to completion?

Sodium hydroxide reacts with carbon dioxide as follows: \(2 \mathrm{NaOH}(s)+\mathrm{CO}_{2}(g) \longrightarrow \mathrm{Na}_{2} \mathrm{CO}_{3}(s)+\mathrm{H}_{2} \mathrm{O}(l)\). Which is the limiting reactant when 1.85 mol NaOH and 1.00 mol CO2 are allowed to react? How many moles of Na2CO3 can be produced? How many moles of the excess reactant remain after the completion of the reaction? Text Transcription: 2NaOH(s)+CO_2(g) longrightarrow Na_2CO_3(s)+H_2O(l)

Aluminum hydroxide reacts with sulfuric acid as follows: \(2 \mathrm{Al}(\mathrm{OH})_{3}(s)+3 \mathrm{H}_{2} \mathrm{SO}_{4}(a q) \longrightarrow \mathrm{Al}_{2}\left(\mathrm{SO}_{4}\right)_{3}(a q)+6 \mathrm{H}_{2} \mathrm{O}(l)\). Which is the limiting reactant when 0.500 mol Al(OH)3 and 0.500 mol H2SO4 are allowed to react? How many moles of Al2(SO4)3 can form under these conditions? How many moles of the excess reactant remain after the completion of the reaction? Text Transcription: 2Al(OH)_3(s)+3H_2SO_4(aq) longrightarrow Al_2(SO_4)_3(aq)+6H_2O(l)

The fizz produced when an Alka-Seltzer tablet is dissolved in water is due to the reaction between sodium bicarbonate (NaHCO3) and citric acid (H3C6H5O7): \(3 \mathrm{NaHCO}_{3}(a q)+\mathrm{H}_{3} \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{O}_{7}(a q) \longrightarrow\) \(3 \mathrm{CO}_{2}(g)+3 \mathrm{H}_{2} \mathrm{O}(l)+\mathrm{Na}_{3} \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{O}_{7}(a q)\). In a certain experiment 1.00 g of sodium bicarbonate and 1.00 g of citric acid are allowed to react. (a) Which is the limiting reactant? (b) How many grams of carbon dioxide form? (c) How many grams of the excess reactant remain after the limiting reactant is completely consumed? Text Transcription: 3NaHCO_3(aq)+H_3C_6H_5O_7(aq) longrightarrow 3CO_2(g)+3H_2O(l)+Na_3C_6H_5O_7(aq)

One of the steps in the commercial process for converting ammonia to nitric acid is the conversion of NH3 to NO: \(4 \mathrm{NH}_{3}(g)+5 \mathrm{O}_{2}(g) \longrightarrow 4 \mathrm{NO}(g)+6 \mathrm{H}_{2} \mathrm{O}(g)\). In a certain experiment, 2.00 g of NH3 reacts with 2.50 g of O2. (a) Which is the limiting reactant? (b) How many grams of NO and H2O form? (c) How many grams of the excess reactant remain after the limiting reactant is completely consumed? (d) Show that your calculations in parts (b) and (c) are consistent with the law of conservation of mass. Text Transcription: 4NH_3(g)+5O_2(g) longrightarrow 4NO(g)+6H_2O(g)

Solutions of sodium carbonate and silver nitrate react to form solid silver carbonate and a solution of sodium nitrate. A solution containing 3.50 g of sodium carbonate is mixed with one containing 5.00 g of silver nitrate. How many grams of sodium carbonate, silver nitrate, silver carbonate, and sodium nitrate are present after the reaction is complete?

Solutions of sulfuric acid and lead(II) acetate react to form solid lead(II) sulfate and a solution of acetic acid. If 5.00 g of sulfuric acid and 5.00 g of lead(II) acetate are mixed, calculate the number of grams of sulfuric acid, lead(II) acetate, lead(II) sulfate, and acetic acid present in the mixture after the reaction is complete.

When benzene (C6H6) reacts with bromine (Br2), bromobenzene (C6H5Br) is obtained: \(\mathrm{C}_{6} \mathrm{H}_{6}+\mathrm{Br}_{2} \longrightarrow \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{Br}+\mathrm{HBr}\) (a) When 30.0 g of benzene reacts with 65.0 g of bromine, what is the theoretical yield of bromobenzene? (b) If the actual yield of bromobenzene is 42.3 g, what is the percentage yield? Text Transcription: C_6H_6+Br_2 longrightarrow C_6H_5Br+HBr

When ethane (C2H6) reacts with chlorine (Cl2), the main product is C2H5Cl, but other products containing Cl, such as C2H4Cl2, are also obtained in small quantities. The formation of these other products reduces the yield of C2H5Cl. (a) Calculate the theoretical yield of C2H5Cl when 125 g of C2H6 reacts with 255 g of Cl2, assuming that C2H6 and Cl2 react only to form C2H2Cl and HCl. (b) Calculate the percent yield of C2H5Cl if the reaction produces 206 g of C2H5Cl.

Hydrogen sulfide is an impurity in natural gas that must be removed. One common removal method is called the Claus process, which relies on the reaction: \(8 \mathrm{H}_{2} \mathrm{~S}(g)+4 \mathrm{O}_{2}(g) \longrightarrow \mathrm{S}_{8}(l)+8 \mathrm{H}_{2} \mathrm{O}(g)\). Under optimal conditions the Claus process gives 98% yield of S8 from H2S. If you started with 30.0 g of H2S and 50.0 g of O2, how many grams of S8 would be produced, assuming 98% yield? Text Transcription: 8H_2S(g)+4O_2(g) longrightarrow S_8(l)+8H_2O(g)

When hydrogen sulfide gas is bubbled into a solution of sodium hydroxide, the reaction forms sodium sulfide and water. How many grams of sodium sulfide are formed if 1.25 g of hydrogen sulfide is bubbled into a solution containing 2.00 g of sodium hydroxide, assuming that the sodium sulfide is made in 92.0% yield?

Write the balanced chemical equations for (a) the complete combustion of acetic acid (CH3COOH), the main ingredient in vinegar; (b) the decomposition of solid calcium hydroxide into solid calcium oxide (lime) and water vapor; (c) the combination reaction between nickel metal and chlorine gas.

If 1.5 mol C2H5OH, 1.5 mol C3H8, and 1.5 mol CH3CH2COCH3 are completely combusted in oxygen, which produces the largest number of moles of H2O? Which produces the least? Explain.

The effectiveness of nitrogen fertilizers depends on both their ability to deliver nitrogen to plants and the amount of nitrogen they can deliver. Four common nitrogen-containing fertilizers are ammonia, ammonium nitrate, ammonium sulfate, and urea [(NH2)2CO]. Rank these fertilizers in terms of the mass percentage nitrogen they contain.

(a) The molecular formula of acetylsalicylic acid (aspirin), one of the most common pain relievers, is C9H8O4. How many moles of C9H8O4 are in a 0.500-g tablet of aspirin? Assume the tablet is composed entirely of aspirin. (b) How many molecules of C9H8O4 are in this tablet? (c) How many carbon atoms are in the tablet?

Very small semiconductor crystals, composed of approximately 1000 to 10,000 atoms, are called quantum dots. Quantum dots made of the semiconductor CdSe are now being used in electronic reader and tablet displays because they emit light efficiently and in multiple colors, depending on dot size. The density of CdSe is 5.82 g/cm3. (a) What is the mass of one 2.5-nm CdSe quantum dot? (b) CdSe quantum dots that are 2.5 nm in diameter emit blue light upon stimulation. Assuming that the dot is a perfect sphere and that the empty space in the dot can be neglected, calculate how many Cd atoms are in one quantum dot of this size. (c) What is the mass of one 6.5-nm CdSe quantum dot? (d) CdSe quantum dots that are 6.5 nm in diameter emit red light upon stimulation. Assuming that the dot is a perfect sphere, calculate how many Cd atoms are in one quantum dot of this size. (e) If you wanted to make one 6.5-nm dot from multiple 2.5- nm dots, how many 2.5-nm dots would you need, and how many CdSe formula units would be left over, if any?

(a) One molecule of the antibiotic penicillin G has a mass of 5.342 10-21 g. What is the molar mass of penicillin G? (b) Hemoglobin, the oxygen-carrying protein in red blood cells, has four iron atoms per molecule and contains 0.340% iron by mass. Calculate the molar mass of hemoglobin.

Serotonin is a compound that conducts nerve impulses in the brain. It contains 68.2% C, 6.86% H, 15.9% N, and 9.08% O. Its molar mass is 176 g/mol. Determine its molecular formula.

The koala dines exclusively on eucalyptus leaves. Its digestive system detoxifies the eucalyptus oil, a poison to other animals. The chief constituent in eucalyptus oil is a substance called eucalyptol, which contains 77.87% C, 11.76% H, and the remainder O. (a) What is the empirical formula for this substance? (b) A mass spectrum of eucalyptol shows a peak at about 154 amu. What is the molecular formula of the substance?

Vanillin, the dominant flavoring in vanilla, contains C, H, and O. When 1.05 g of this substance is completely combusted, 2.43 g of CO2 and 0.50 g of H2O are produced. What is the empirical formula of vanillin?

An organic compound was found to contain only C, H, and Cl. When a 1.50-g sample of the compound was completely combusted in air, 3.52 g of CO2 was formed. In a separate experiment, the chlorine in a 1.00-g sample of the compound was converted to 1.27 g of AgCl. Determine the empirical formula of the compound.

A compound, KBrO????, where ???? is unknown, is analyzed and found to contain 52.92% Br. What is the value of ?????

An element X forms an iodide (XI3) and a chloride (XCl3). The iodide is quantitatively converted to the chloride when it is heated in a stream of chlorine: \(2 \mathrm{XI}_{3}+3 \mathrm{Cl}_{2} \longrightarrow 2 \mathrm{XCl}_{3}+3 \mathrm{I}_{2}\). If 0.5000 g of XI3 is treated with chlorine, 0.2360 g of XCl3 is obtained. (a) Calculate the atomic weight of the element X. (b) Identify the element X. Text Transcription: 2XI_3+3Cl_2 longrightarrow 2XCl_3+3I_2

A method used by the U.S. Environmental Protection Agency (EPA) for determining the concentration of ozone in air is to pass the air sample through a “bubbler” containing sodium iodide, which removes the ozone according to the following equation: \(\mathrm{O}_{3}(g)+2 \mathrm{NaI}(a q)+\mathrm{H}_{2} \mathrm{O}(l)\) \(\mathrm{O}_{2}(g)+\mathrm{I}_{2}(s)+2 \mathrm{NaOH}(a q)\) (a) How many moles of sodium iodide are needed to remove 5.95 10-6 mol of O3? (b) How many grams of sodium iodide are needed to remove 1.3 mg of O3? Text Transcription: O_3(g)+2NaI(aq)+H_2O(l) O_2(g)+I_2(s)+2NaOH(aq)

Identify the alkanes corresponding to each of the drawings shown.

The fat stored in a camel’s hump is a source of both energy and water. Calculate the mass of H2O produced by the metabolism of 1.0 kg of fat, assuming the fat consists entirely of tristearin (C57H110O6), a typical animal fat, and assuming that during metabolism, tristearin reacts with O2 to form only CO2 and H2O.

When hydrocarbons are burned in a limited amount of air, both CO and CO2 form. When 0.450 g of a particular hydrocarbon was burned in air, 0.467 g of CO, 0.733 g of CO2, and 0.450 g of H2O were formed. (a) What is the empirical formula of the compound? (b) How many grams of O2 were used in the reaction? (c) How many grams would have been required for complete combustion?

A mixture of N2(g) and H2(g) reacts in a closed container to form ammonia, NH3(g). The reaction ceases before either reactant has been totally consumed. At this stage 3.0 mol N2, 3.0 mol H2, and 3.0 mol NH3 are present. How many moles of N2 and H2 were present originally?

A mixture containing KClO3, K2CO3, KHCO3, and KCl was heated, producing CO2, O2, and H2O gasses according to the following equations: \(2 \mathrm{KClO}_{3}(s) \longrightarrow 2 \mathrm{KCl}(s)+3 \mathrm{O}_{2}(g)\) \(2 \mathrm{KHCO}_{3}(s) \longrightarrow \mathrm{K}_{2} \mathrm{O}(s)+\mathrm{H}_{2} \mathrm{O}(g)+2 \mathrm{CO}_{2}(g)\) \(\mathrm{K}_{2} \mathrm{CO}_{3}(s) \longrightarrow \mathrm{K}_{2} \mathrm{O}(s)+\mathrm{CO}_{2}(g)\). The KCl does not react under the conditions of the reaction. If 100.0 g of the mixture produces 1.80 g of H2O, 13.20 g of CO2, and 4.00 g of O2, what was the composition of the original mixture? (Assume complete decomposition of the mixture.) Text Transcription: 2KClO_3(s) longrightarrow 2KCl(s)+3O_2(g) 2KHCO_3(s) longrightarrow K_2O(s)+H_2O(g)+2CO_2(g) K_2CO_3(s) longrightarrow K_2O(s)+CO_2(g)

When a mixture of 10.0 g of acetylene (C2H2) and 10.0 g of oxygen (O2) is ignited, the resulting combustion reaction produces CO2 and H2O. (a) Write the balanced chemical equation for this reaction. (b) Which is the limiting reactant? (c) How many grams of C2H2, O2, CO2, and H2O are present after the reaction is complete?

The semiconductor gallium arsenide, GaAs, is used in high speed integrated circuits, light-emitting diodes, and solar cells. Its density is 5.32 g/cm3. It can be made by reacting trimethylgallium, (CH3)3Ga, with arsine gas, AsH3. The other product of the reaction is methane, CH4. (a) If you reacted 450.0 g of trimethylgallium with 300.0 g of arsine, what mass of GaAs could you make? (b) Which reactant, if any, would be left over, and how many moles of the leftover reactant would remain? (c) One application of GaAs uses it as a thin film. If you take the mass of GaAs from part (a) and make a 40-nm thin film from it, what area, in cm2, would it cover? Recall that 1 nm = 1 10-9 m.

Paclitaxel, C47H51NO14, is an anticancer compound that is difficult to make in the lab. One reported synthesis requires 11 steps, and the final yield of paclitaxel is only 5%. Assuming all steps have equivalent yields, what is the average percent yield for each step in the synthesis?

Consider a sample of calcium carbonate in the form of a cube measuring 2.005 in. on each edge. If the sample has a density of 2.71 g/cm3, how many oxygen atoms does it contain?

(a) You are given a cube of silver metal that measures 1.000 cm on each edge. The density of silver is 10.5 g/cm3. How many atoms are in this cube? (b) Because atoms are spherical, they cannot occupy all of the space of the cube. The silver atoms pack in the solid in such a way that 74% of the volume of the solid is actually filled with the silver atoms. Calculate the volume of a single silver atom. (c) Using the volume of a silver atom and the formula for the volume of a sphere, calculate the radius in angstroms of a silver atom.

(a) If an automobile travels 225 mi with a gas mileage of 20.5 mi/gal, how many kilograms of CO2 are produced? Assume that the gasoline is composed of octane, C8H18(l), whose density is 0.692 g/mL. (b) Repeat the calculation for a truck that has a gas mileage of 5 mi/gal.

Section 2.9 introduced the idea of structural isomerism, with 1-propanol and 2-propanol as examples. Determine which of these properties would distinguish these two substances: (a) boiling point, (b) combustion analysis results, (c) molecular weight, (d) density at a given temperature and pressure. You can check on the properties of these two compounds in Wolfram Alpha (http://www.wolframalpha.com/) or the CRC Handbook of Chemistry and Physics.

A particular coal contains 2.5% sulfur by mass. When this coal is burned at a power plant, the sulfur is converted into sulfur dioxide gas, which is a pollutant. To reduce sulfur dioxide emissions, calcium oxide (lime) is used. The sulfur dioxide reacts with calcium oxide to form solid calcium sulfite. (a) Write the balanced chemical equation for the reaction. (b) If the coal is burned in a power plant that uses 2000.0 tons of coal per day, what mass of calcium oxide is required daily to eliminate the sulfur dioxide? (c) How many grams of calcium sulfite does this power plant produce daily?

Hydrogen cyanide, HCN, is a poisonous gas. The lethal dose is approximately 300 mg HCN per kilogram of air when inhaled. (a) Calculate the amount of HCN that gives the lethal dose in a small laboratory room measuring 12 15 8.0 ft. The density of air at 26 °C is 0.00118 g/cm3. (b) If the HCN is formed by reaction of NaCN with an acid such as H2SO4, what mass of NaCN gives the lethal dose in the room? \(2 \mathrm{NaCN}(s)+\mathrm{H}_{2} \mathrm{SO}_{4}(a q) \longrightarrow \mathrm{Na}_{2} \mathrm{SO}_{4}(a q)+2 \mathrm{HCN}(g)\) (c) HCN forms when synthetic fibers containing Orlon® or Acrilan® burn. Acrilan® has an empirical formula of CH2CHCN, so HCN is 50.9% of the formula by mass. A rug measures 12 15 ft and contains 30 oz of Acrilan® fibers per square yard of carpet. If the rug burns, will a lethal dose of HCN be generated in the room? Assume that the yield of HCN from the fibers is 20% and that the carpet is 50% consumed. Text Transcription: 2NaCN(s)+H_2SO_4(aq) longrightarrow Na_2SO_4(aq)+2HCN(g)

The source of oxygen that drives the internal combustion engine in an automobile is air. Air is a mixture of gasses, principally N2(?79%) and O2(?20%). In the cylinder of an automobile engine, nitrogen can react with oxygen to produce nitric oxide gas, NO. As NO is emitted from the tailpipe of the car, it can react with more oxygen to produce nitrogen dioxide gas. (a) Write balanced chemical equations for both reactions. (b) Both nitric oxide and nitrogen dioxide are pollutants that can lead to acid rain and global warming; collectively, they are called “NOx” gasses. In 2009, the United States emitted an estimated 19 million tons of nitrogen dioxide into the atmosphere. How many grams of nitrogen dioxide is this? (c) The production of NOx gasses is an unwanted side reaction of the main engine combustion process that turns octane, C8H18, into CO2 and water. If 85% of the oxygen in an engine is used to combust octane and the remainder used to produce nitrogen dioxide, calculate how many grams of nitrogen dioxide would be produced during the combustion of 500 g of octane.

The thermite reaction, \(\mathrm{Fe}_{2} \mathrm{O}_{3}+\mathrm{Al} \rightarrow \mathrm{Al}_{2} \mathrm{O}_{3}+\mathrm{Fe}\). produces so much heat that the Fe product melts. This reaction is used industrially to weld metal parts under water, where a torch cannot be employed. It is also a favorite chemical demonstration in the lecture hall (on a small scale). (a) Balance the chemical equation for the thermite reaction, and include the proper states of matter. (b) Calculate how many grams of aluminum are needed to completely react with 500.0 g of Fe2O3 in this reaction. (c) This reaction produces 852 kJ of heat per mole of Fe2O3 reacted. How many grams of Fe2O3 are needed to produce 1.00 104 kJ of heat? (d) If you performed the reverse reaction— aluminum oxide plus iron makes iron oxide plus aluminum—would that reaction have heat as a reactant or a product? Text Transcription: Fe_2O_3+Al rightarrow Al_2O_3+Fe

One of the most bizarre reactions in chemistry is called the Ugi reaction: \(\mathrm{R}_{1} \mathrm{C}(=\mathrm{O}) \mathrm{R}_{2}+\mathrm{R}_{3}-\mathrm{NH}_{2}+\mathrm{R}_{4} \mathrm{COOH}+\mathrm{R}_{5} \mathrm{NC} \rightarrow\) \(\mathrm{R}_{4} \mathrm{C}(=\mathrm{O}) \mathrm{N}\left(\mathrm{R}_{3}\right) \mathrm{C}\left(\mathrm{R}_{1} \mathrm{R}_{2}\right) \mathrm{C}=\mathrm{ONHR}_{5}+\mathrm{H}_{2} \mathrm{O}\) (a) Write out the balanced chemical equation for the Ugi reaction, for the case where R = CH3CH2CH2CH2CH2CH2— (this is called the hexyl group) for all compounds. (b) What mass of the “hexyl Ugi product” would you form if 435.0 mg of CH3 CH2CH2CH2CH2CH2NH2 was the limiting reactant? Text Transcription: R_1C(=O)R_2+R_3-NH_2+R_4COOH+R_5NC rightarrow R_4C(=O)N(R_3) C(R_1R_2)C=ONHR_5+H_2O

Identify the alkanes corresponding to each of the drawings shown.

Acetylcholine is a neurotransmitter in the central nervous system in humans. Sighting along the C ? C bond, draw Newman projection formulas for the anti and gauche conformations of acetylcholine.

As calculated by molecular mechanics, Estrain for the eclipsed conformation of butane is +9.3 kJ/mol. On the basis of this and the Estrain values just cited, calculate the activation energy for rotation about the C(2) C(3) bond.

Given the following partial structure, add a substituent X to C-1 so that it satisfies the indicated stereochemical requirement. What is the A?C?C?X torsion (dihedral) angle in each? (a) Anti to A (b) Gauche to A (c) Anti to C-3 (d) Gauche to C-3

The following questions relate to a cyclohexane ring in the chair conformation shown. (a) Is a methyl group at C-6 that is “down” axial or equatorial? (b) Is a methyl group that is “up” at C-1 more or less stable than a methyl group that is up at C-4? (c) Place a methyl group at C-3 in its most stable orientation. Is it up or down?

Chrysanthemic acid, from the chrysanthemum flower, is a naturally occurring insecticide, with the constitution indicated. Draw the structures of the cis and trans stereoisomers of chrysanthemic acid.

Based on what you know about disubstituted cyclohexanes, which of the following two stereoisomeric 1,3,5-trimethylcyclohexanes would you expect to be more stable?

Cubane (C4H8) is the common name of the polycyclic hydrocarbon shown. As its name implies, its structure is that of a cube. How many rings are present in cubane according to the bonddisconnection rule?

Vetiver, a soothing oil popular in aromatherapy (Figure 3.21 ), contains \(\beta\)-vetivone, which can be viewed as a derivative of compound A. What is the IUPAC name of A? Text Transcription: beta

Geosmin is a natural product that smells like dirt. It is produced by several microorganisms and can be obtained from beet extracts. Complete the following decalin ring skeleton, placing the substituents of geosmin in their proper orientations.

Give the IUPAC names of each of the following:

Draw Newman projections for the gauche and anti conformations of 1,2-dichloroethane (ClCH2CH2Cl).

Identify all atoms that are (a) anti and (b) gauche to bromine in the conformation shown for CH3CH2CH2Br.

Excluding compounds that contain methyl or ethyl groups, write structural formulas for all the bicyclic isomers of (a) C5H8 and (b) C6H10.

Biological oxidation of hydrocarbons is a commonly observed process. (a) To what class of hydrocarbons does the reactant in the following equation belong? What is its IUPAC name? (b) Identify by IUPAC locant the carbon that is oxidized in the formation of each product. (c) How are alcohols A, B, and C related? Are they constitutional isomers or stereoisomers?

A typical steroid skeleton is shown along with the numbering scheme used for this class of compounds. Specify in each case whether the designated substituent is axial or equatorial. (a) Substituent at C-1 cis to the methyl groups (b) Substituent at C-4 cis to the methyl groups (c) Substituent at C-7 trans to the methyl groups (d) Substituent at C-11 trans to the methyl groups (e) Substituent at C-12 cis to the methyl groups

Repeat the preceding problem for the stereoisomeric steroidal skeleton having a cis ring fusion between the first two rings.

Determine whether the two structures in each of the following pairs represent constitutional isomers, different conformations of the same compound, or stereoisomers that cannot be interconverted by rotation about single bonds. (d) cis-1,2-Dimethylcyclopentane and trans-1,3-dimethylcyclopentane

Select the compounds in each group that are isomers and specify whether they are constitutional isomers or stereoisomers.

Oxidation of 4-tert-butylthiane proceeds according to the equation shown, but the resulting sulfoxide is a mixture of two isomers. Explain by writing appropriate structural formulas.

The following are representations of two forms of glucose. The six-membered ring is known to exist in a chair conformation in each form. Draw clear representations of the most stable conformation of each. Are they two different conformations of the same molecule, or are they stereoisomers that cannot be interconverted by rotation about single bonds? Which substituents (if any) occupy axial sites?

Write a structural formula for the most stable chair conformation of each of the following compounds: (a) cis-1-Isopropyl-3-methylcyclohexane (b) trans-1-Isopropyl-3-methylcyclohexane (c) cis-1-tert-Butyl-4-ethylcyclohexane (d) cis-1,1,3,4-Tetramethylcyclohexane (e)

Even though the methyl group occupies an equatorial site, the conformation shown is not the most stable one for methylcyclohexane. Explain.

Which do you expect to be the more stable conformation of cis-1,3-dimethylcyclobutane, A or B? Why?

Arrange the trimethylcyclohexane isomers shown in order of decreasing stability.

Identify the more stable stereoisomer in each of the following pairs, and give the reason for your choice: (a) cis- or trans-1-Isopropyl-2-methylcyclohexane (b) cis- or trans-1-Isopropyl-3-methylcyclohexane (c) cis- or trans-1-Isopropyl-4-methylcyclohexane

One of the following two stereoisomers is 20 kJ/mol (4.9 kcal/mol) less stable than the other. Indicate which isomer is the less stable, and identify the reason for its decreased stability.

In each of the following groups of compounds, identify the one with the largest heat of combustion and the one with the smallest. In which cases can a comparison of heats of combustion be used to assess relative stability? (a) Cyclopropane, cyclobutane, cyclopentane (b) cis-1,2-Dimethylcyclopentane, methylcyclohexane, 1,1,2,2-tetramethylcyclopropane

The heats of combustion of the more and less stable stereoisomers of the 1,2-, 1,3-, and 1,4-dimethylcyclohexanes are given here. The values are higher for the 1,2- dimethylcyclohexanes than for the 1,3- and 1,4-isomers. Suggest an explanation. Dimethylcyclohexane 1,2 1,3 1,4 Heats of combustion (kJ/mol): More stable stereoisomer 5217 5212 5212 Less stable stereoisomer 5223 5219 5219

The measured dipole moment of ClCH2CH2Cl is 1.12 D. Which one of the following statements about 1,2-dichloroethane is false? (1) It may exist entirely in the anti conformation. (2) It may exist entirely in the gauche conformation. (3) It may exist as a mixture of anti and gauche conformations.

Which one of the C2H3Cl3 isomers has the largest dipole moment?

Five- and six-membered ring structures are common in carbohydrates and are often in equilibrium with each other. The five-membered ring structures are called furanose forms; the six-membered ring structures are pyranose forms. d-Ribose, especially in its ?-furanose form, is a familiar carbohydrate. The \(\beta\)-furanose and \(\beta\)-pyranose forms of d-ribose are: A. Conformational isomers B. Constitutional isomers C. Resonance forms D. Stereoisomers Text Transcription: beta

Five- and six-membered ring structures are common in carbohydrates and are often in equilibrium with each other. The five-membered ring structures are called furanose forms; the six-membered ring structures are pyranose forms. d-Ribose, especially in its ?-furanose form, is a familiar carbohydrate. What is the orientation of the OH groups at C-2 and C-3 in the \(\beta\)-pyranose form of d-ribose? A. Both are axial. B. Both are equatorial. C. C-2 is axial; C-3 is equatorial. D. C-2 is equatorial; C-3 is axial. Text Transcription: beta

Five- and six-membered ring structures are common in carbohydrates and are often in equilibrium with each other. The five-membered ring structures are called furanose forms; the six-membered ring structures are pyranose forms. d-Ribose, especially in its ?-furanose form, is a familiar carbohydrate. The OH groups at C-2 and C-3 in the \(\beta\)-pyranose form of d-ribose are: A. cis and gauche B. cis and anti C. trans and gauche D. trans and anti Text Transcription: beta

Five- and six-membered ring structures are common in carbohydrates and are often in equilibrium with each other. The five-membered ring structures are called furanose forms; the six-membered ring structures are pyranose forms. d-Ribose, especially in its ?-furanose form, is a familiar carbohydrate. All of the OH groups of the \(\beta\)-pyranose form of d-xylose are equatorial. Which of the following is the \(\beta\)-furanose form of d-xylose? Text Transcription: beta

Five- and six-membered ring structures are common in carbohydrates and are often in equilibrium with each other. The five-membered ring structures are called furanose forms; the six-membered ring structures are pyranose forms. d-Ribose, especially in its ?-furanose form, is a familiar carbohydrate. The carbohydrate shown here is a component of a drug used in veterinary medicine. Which is its most stable pyranose conformation?

Five- and six-membered ring structures are common in carbohydrates and are often in equilibrium with each other. The five-membered ring structures are called furanose forms; the six-membered ring structures are pyranose forms. d-Ribose, especially in its ?-furanose form, is a familiar carbohydrate. What are the O C(1) C(2) O and O C(2) C(3) O torsion (dihedral) angles in the \(\beta\)-pyranose form of d-ribose? A. 60° and 180°, respectively. B. 180° and 60°, respectively. C. Both are 60°. D. Both are 180°. Text Transcription: beta

Find the conformations in Figure 3.4 in which the hydrogens marked in red are (a) gauche and (b) anti.

Sketch a potential energy diagram for rotation around a carbon–carbon bond in propane. Identify each potential energy maximum and minimum with a structural formula that shows the conformation of propane at that point. Does your diagram more closely resemble that of ethane or of butane? Would you expect the activation energy for bond rotation in propane to be more than or less than that of ethane? Of butane?

The heats of combustion of ethylcyclopropane and methylcyclobutane have been measured as 3352 and 3384 kJ/mol (801.2 and 808.8 kcal/mol). Assign the correct heat of combustion to each isomer.

Draw the most stable conformation of 1-tert-butyl-1-methylcyclohexane.

Exclusive of compounds with double bonds, four hydrocarbons are constitutional isomers of cis- and trans-1,2-dimethylcyclopropane. Identify these compounds.

Write structural formulas for the most stable conformation of each of the following compounds: (a) trans-1-tert-Butyl-3-methylcyclohexane (b) cis-1-tert-Butyl-3-methylcyclohexane (c) trans-1-tert-Butyl-4-methylcyclohexane (d) cis-1-tert-Butyl-4-methylcyclohexane

Use the bond-cleavage criterion to verify that camphene is bicyclic.

Write structural formulas for each of the following bicyclic hydrocarbons: (a) Bicyclo[2.2.1]heptane (b) 1,7,7-Trimethylbicyclo[2.2.1]heptane (c) Bicyclo[3.1.1]heptane

Draw what you would expect to be the most stable conformation of the piperidine derivative in which the hydrogen bonded to nitrogen has been replaced by methyl.

Draw (a) a Newman projection of the most stable conformation sighting down the C-3 C-4 bond and (b) a bond-line depiction of 2,2,5,5-tetramethylhexane.

Sight down the C-2 C-3 bond, and draw Newman projection formulas for the (a) Most stable conformation of 2,2-dimethylbutane (b) Two most stable conformations of 2-methylbutane (c) Two most stable conformations of 2,3-dimethylbutane

One of the staggered conformations of 2-methylbutane in Problem 3.33b is more stable than the other. Which one is more stable? Why?

Sketch an approximate potential energy diagram for rotation about the carbon–carbon bond in 2,2-dimethylpropane similar to that shown in Figures 3.4 and 3.7. Does the form of the potential energy curve of 2,2-dimethylpropane more closely resemble that of ethane or that of butane?

Repeat Problem 3.35 for the case of 2-methylbutane.

One stereoisomer of 1,1,3,5-tetramethylcyclohexane is 15 kJ/mol (3.7 kcal/mol) less stable than the other. Indicate which isomer is the less stable, and identify the reason for its decreased stability.

Which one of the dichlorocyclohexane isomers has the smallest dipole moment?