Cortisol (m _ 362.47 g/mol), one of the major steroid hormones, is a key factor in the

The atomic mass of Cl is 35.45 amu, and the atomic mass of Al is 26.98 amu. What are the masses in grams of 3 mol of Al atoms and of 2 mol of Cl atoms?

(a) How many moles of C atoms are in 1 mol of sucrose (C12H22O11)? (b) How many C atoms are in 2 mol of sucrose?

Why might the expression 1 mol of chlorine be confusing? What change would remove any uncertainty? For what other elements might a similar confusion exist? Why?

How is the molecular mass of a compound the same as the molar mass, and how is it different?

What advantage is there to using a counting unit (the mole) in chemistry rather than a mass unit?

You need to calculate the number of P4 molecules that can form from 2.5 g of Ca3(PO4)2. Explain how you would proceed. (That is, write a solution Plan, without actually doing any calculations.)

Each of the following balances weighs the indicated numbers of atoms of two elements: Which elementleft, right, or neither, (a) Has the higher molar mass? (b) Has more atoms per gram? (c) Has fewer atoms per gram? (d) Has more atoms per mole?

Calculate the molar mass of each of the following: (a) Sr(OH)2 (b) N2O3 (c) NaClO3 (d) Cr2O3

Calculate the molar mass of each of the following: (a) (NH4)3PO4 (b) CH2Cl2 (c) CuSO4 5H2O (d) BrF3

Calculate the molar mass of each of the following: (a) SnO (b) BaF2 (c) Al2(SO4)3 (d) MnCl2

Calculate the molar mass of each of the following: (a) N2O4 (b) C4H9OH (c) MgSO4 7H2O (d) Ca(C2H3O2)2

Calculate each of the following quantities: (a) Mass in grams of 0.68 mol of KMnO4 (b) Moles of O atoms in 8.18 g of Ba(NO3)2 (c) Number of O atoms in 7.3_10_3 g of CaSO4 2H2O

Calculate each of the following quantities: (a) Mass in kilograms of 4.6_1021 molecules of NO2 (b) Moles of Cl atoms in 0.0615 g of C2H4Cl2 (c) Number of H_ ions in 5.82 g of SrH2

Calculate each of the following quantities: (a) Mass in grams of 6.44_10_2 mol of MnSO4 (b) Moles of compound in 15.8 kg of Fe(ClO4)3 (c) Number of N atoms in 92.6 mg of NH4NO2

Calculate each of the following quantities: (a) Total number of ions in 38.1 g of SrF2 (b) Mass in kilograms of 3.58 mol of CuCl2_2H2O (c) Mass in milligrams of 2.88_1022 formula units of Bi(NO3)3_5H2O

Calculate each of the following quantities: (a) Mass in grams of 8.35 mol of copper(I) carbonate (b) Mass in grams of 4.04_1020 molecules of dinitrogen pentaoxide (c) Number of moles and formula units in 78.9 g of sodium perchlorate (d) Number of sodium ions, perchlorate ions, Cl atoms, and O atoms in the mass of compound in part (c)

Calculate each of the following quantities: (a) Mass in grams of 8.42 mol of chromium(III) sulfate decahydrate (b) Mass in grams of 1.83_1024 molecules of dichlorine heptaoxide (c) Number of moles and formula units in 6.2 g of lithium sulfate (d) Number of lithium ions, sulfate ions, S atoms, and O atoms in the mass of compound in part (c)

Calculate each of the following: (a) Mass % of H in ammonium bicarbonate (b) Mass % of O in sodium dihydrogen phosphate heptahydrate

Calculate each of the following: (a) Mass % of I in strontium periodate (b) Mass % of Mn in potassium permanganate

Calculate each of the following: (a) Mass fraction of C in cesium acetate (b) Mass fraction of O in uranyl sulfate trihydrate (the uranyl ion is UO2 2_)

Calculate each of the following: (a) Mass fraction of Cl in calcium chlorate (b) Mass fraction of P in tetraphosphorus hexaoxide

Oxygen is required for the metabolic combustion of foods. Calculate the number of atoms in 38.0 g of oxygen gas, the amount absorbed from the lungs at rest in about 15 min.

Cisplatin (right), or Platinol, is used in the treatment of certain cancers. Calculate (a) the moles of compound in 285.3 g of cisplatin; (b) the number of hydrogen atoms in 0.98 mol of cisplatin.

Allyl sulfide (below) gives garlic its characteristic odor. Calculate (a) the mass in grams of 2.63 mol of allyl sulfide; (b) the number of carbon atoms in 35.7 g of allyl sulfide.

Iron reacts slowly with oxygen and water to form a compound commonly called rust (Fe2O3 4H2O). For 45.2 kg of rust, calculate (a) the moles of compound; (b) the moles of Fe2O3; (c) the grams of iron.

Propane is widely used in liquid form as a fuel for barbecue grills and camp stoves. For 85.5 g of propane, calculate (a) the moles of compound; (b) the grams of carbon.

The effectiveness of a nitrogen fertilizer is determined mainly by its mass % N. Rank the following fertilizers, most effective first: potassium nitrate; ammonium nitrate; ammonium sulfate; urea, CO(NH2)2.

The mineral galena is composed of lead(II) sulfide and has an average density of 7.46 g/cm3. (a) How many moles of lead(II) sulfide are in 1.00 ft3 of galena? (b) How many lead atoms are in 1.00 dm3 of galena?

Hemoglobin, a protein in red blood cells, carries O2 from the lungs to the bodys cells. Iron (as ferrous ion, Fe2_) makes up 0.33 mass % of hemoglobin. If the molar mass of hemoglobin is 6.8_104 g/mol, how many Fe2_ ions are in one molecule? (Sample Problems 3.5 to 3.7)

List three ways compositional data may be given in a problem that involves finding an empirical formula.

Which of the following sets of information allows you to obtain the molecular formula of a covalent compound? In each case that allows it, explain how you would proceed (write a solution Plan). (a) Number of moles of each type of atom in a given sample of the compound (b) Mass % of each element and the total number of atoms in a molecule of the compound (c) Mass % of each element and the number of atoms of one element in a molecule of the compound (d) Empirical formula and mass % of each element in the compound (e) Structural formula of the compound

Is MgCl2 an empirical or a molecular formula for magnesium chloride? Explain.

What is the empirical formula and empirical formula mass for each of the following compounds? (a) C2H4 (b) C2H6O2 (c) N2O5 (d) Ba3(PO4)2 (e) Te4I16

What is the empirical formula and empirical formula mass for each of the following compounds? (a) C4H8 (b) C3H6O3 (c) P4O10 (d) Ga2(SO4)3 (e) Al2Br6

What is the molecular formula of each compound? (a) Empirical formula CH2 (m _ 42.08 g/mol) (b) Empirical formula NH2 (m _ 32.05 g/mol) H S C (c) Empirical formula NO2 (_ _ 92.02 g/mol) (d) Empirical formula CHN (_ _ 135.14 g/mol)

What is the molecular formula of each compound? (a) Empirical formula CH (__ 78.11 g/mol) (b) Empirical formula C3H6O2 (_ _ 74.08 g/mol) (c) Empirical formula HgCl (_ _ 472.1 g/mol) (d) Empirical formula C7H4O2 (_ _ 240.20 g/mol)

Find the empirical formula of the following compounds: (a) 0.063 mol of chlorine atoms combined with 0.22 mol of oxygen atoms (b) 2.45 g of silicon combined with 12.4 g of chlorine (c) 27.3 mass % carbon and 72.7 mass % oxygen

Find the empirical formula of the following compounds: (a) 0.039 mol of iron atoms combined with 0.052 mol of oxygen atoms (b) 0.903 g of phosphorus combined with 6.99 g of bromine (c) A hydrocarbon with 79.9 mass % carbon

An oxide of nitrogen contains 30.45 mass % N. (a) What is the empirical formula of the oxide? (b) If the molar mass is 905 g/mol, what is the molecular formula?

Achloride of silicon contains 79.1 mass % Cl. (a) What is the empirical formula of the chloride? (b) If the molar mass is 269 g/mol, what is the molecular formula?

A sample of 0.600 mol of a metal M reacts completely with excess fluorine to form 46.8 g of MF2. (a) How many moles of F are in the sample of MF2 that forms? (b) How many grams of M are in this sample of MF2? (c) What element is represented by the symbol M?

A 0.370-mol sample of a metal oxide (M2O3) weighs 55.4 g. (a) How many moles of O are in the sample? (b) How many grams of M are in the sample? (c) What element is represented by the symbol M?

Nicotine is a poisonous, addictive compound found in tobacco. Asample of nicotine contains 6.16 mmol of C, 8.56 mmol of H, and 1.23 mmol of N [1 mmol (1 millimole) _ 10_3 mol]. What is the empirical formula?

Cortisol (m _ 362.47 g/mol), one of the major steroid hormones, is a key factor in the synthesis of protein. Its profound effect on the reduction of inflammation explains its use in the treatment of rheumatoid arthritis. Cortisol is 69.6% C, 8.34% H, and 22.1% O by mass. What is its molecular formula?

Acetaminophen (below) is a popular nonaspirin, over-thecounter pain reliever. What is the mass % of each element in acetaminophen?

Menthol (m _ 156.3 g/mol), a strong-smelling substance used in cough drops, is a compound of carbon, hydrogen, and oxygen. When 0.1595 g of menthol was subjected to combustion analysis, it produced 0.449 g of CO2 and 0.184 g of H2O. What is menthols molecular formula?

What three types of information does a balanced chemical equation provide? How?

How does a balanced chemical equation apply the law of conservation of mass?

In the process of balancing the equation Student I writes: Al _ Cl2 Student II writes: Al _ Cl2 _ Cl AlCl3 Student III writes: 2Al _ 3Cl2 2AlCl3 Is the approach of Student I valid? Student II? Student III? Explain.

The scenes below represent a chemical reaction between elements A (red) and B (green): Which best represents the balanced equation for the reaction? (a) 2A_ 2B A2 _ B2 (b) A2 _ B2 2AB (c) B2 _ 2AB 2B2 _A2 (d) 4A2 _ 4B2 8AB

Write balanced equations for each of the following by inserting the correct coefficients in the blanks: (a) __Cu(s) _ __S8(s) __Cu2S(s) (b) __P4O10(s) _ __H2O(l) __H3PO4(l) (c) __B2O3(s) _ __NaOH(aq) __Na3BO3(aq) _ __H2O(l) (d) __CH3NH2(g) _ __O2(g) __CO2(g) _ __H2O(g) _ __N2(g)

Write balanced equations for each of the following by inserting the correct coefficients in the blanks: (a) __Cu(NO3)2(aq) _ __KOH(aq) __Cu(OH)2(s) _ __KNO3(aq) (b) __BCl3(g) _ __H2O(l) __H3BO3(s) _ __HCl(g) (c) __CaSiO3(s) _ __HF(g) __SiF4(g) _ __CaF2(s) _ __H2O(l) (d) __(CN)2(g) _ __H2O(l) __H2C2O4(aq) _ __NH3(g)

Write balanced equations for each of the following by inserting the correct coefficients in the blanks: (a) __SO2(g) _ __O2(g) __SO3(g) (b) __Sc2O3(s) _ __H2O(l) __Sc(OH)3(s) (c) __H3PO4(aq) _ __NaOH(aq) __Na2HPO4(aq) _ __H2O(l) (d) __C6H10O5(s) _ __O2(g) __CO2(g) _ __H2O(g)

Write balanced equations for each of the following by inserting the correct coefficients in the blanks: (a) __As4S6(s) _ __O2(g) __As4O6(s) _ __SO2(g) (b) __Ca3(PO4)2(s) _ ___SiO2(s) _ __C(s) __P4(g) _ __CaSiO3(l) _ __CO(g) (c) __Fe(s) _ __H2O(g) __Fe3O4(s) _ __H2(g) (d) __S2Cl2(l) _ __NH3(g) __S4N4(s) _ __S8(s) _ __NH4Cl(s) AlCl2 Al _ Cl2AlCl3

Convert the following into balanced equations: (a) When gallium metal is heated in oxygen gas, it melts and forms solid gallium(III) oxide. (b) Liquid hexane burns in oxygen gas to form carbon dioxide gas and water vapor. (c) When solutions of calcium chloride and sodium phosphate are mixed, solid calcium phosphate forms and sodium chloride remains in solution.

Convert the following into balanced equations: (a) When lead(II) nitrate solution is added to potassium iodide solution, solid lead(II) iodide forms and potassium nitrate solution remains. (b) Liquid disilicon hexachloride reacts with water to form solid silicon dioxide, hydrogen chloride gas, and hydrogen gas. (c) When nitrogen dioxide is bubbled into water, a solution of nitric acid forms and gaseous nitrogen monoxide is released.

Loss of atmospheric ozone has led to an ozone hole over Antarctica. The process occurs in part by three consecutive reactions: (1) Chlorine atoms react with ozone (O3) to form chlorine monoxide and molecular oxygen. (2) Chlorine monoxide forms ClOOCl. (3) ClOOCl absorbs sunlight and breaks into chlorine atoms and molecular oxygen. (a) Write a balanced equation for each step. (b) Write an overall balanced equation for the sequence. (Sample Problems 3.10 to 3.14)

What does the term stoichiometrically equivalent molar ratio mean, and how is it applied in solving problems?

The circle below represents a mixture of A2 and B2 before they react to form AB3. (a) What is the limiting reactant? (b) How many molecules of product can form?

Percent yields are generally calculated from mass quantities. Would the result be the same if mole quantities were used instead? Why?

Reactants A and B form product C. Write a detailed Plan to find the mass of C when 25 g of A reacts with excess B.

Reactants D and E form product F. Write a detailed Plan to find the mass of F when 27 g of D reacts with 31 g of E.

Chlorine gas can be made in the laboratory by the reaction of hydrochloric acid and manganese(IV) oxide: 4HCl(aq) _ MnO2(s) MnCl2(aq) _ 2H2O(g) _ Cl2(g) When 1.82 mol of HCl reacts with excess MnO2, (a) how many moles of Cl2 form? (b) How many grams of Cl2 form?

Bismuth oxide reacts with carbon to form bismuth metal: Bi2O3(s) _ 3C(s) 2Bi(s) _ 3CO(g) When 283 g of Bi2O3 reacts with excess carbon, (a) how many moles of Bi2O3 react? (b) How many moles of Bi form?

Potassium nitrate decomposes on heating, producing potassium oxide and gaseous nitrogen and oxygen: 4KNO3(s) 2K2O(s) _ 2N2(g) _ 5O2(g) To produce 56.6 kg of oxygen, how many (a) moles of KNO3 must be heated? (b) Grams of KNO3 must be heated?

Chromium(III) oxide reacts with hydrogen sulfide (H2S) gas to form chromium(III) sulfide and water: Cr2O3(s) _ 3H2S(g) Cr2S3(s) _ 3H2O(l) To produce 421 g of Cr2S3, (a) how many moles of Cr2O3 are required? (b) How many grams of Cr2O3 are required?

Calculate the mass of each product formed when 43.82 g of diborane (B2H6) reacts with excess water: B2H6(g) _ H2O(l) H3BO3(s) _ H2(g) [unbalanced]

Calculate the mass of each product formed when 174 g of silver sulfide reacts with excess hydrochloric acid: Ag2S(s) _ HCl(aq) AgCl(s) _ H2S(g) [unbalanced]

Elemental phosphorus occurs as tetratomic molecules, P4. What mass of chlorine gas is needed to react completely with 455 g of phosphorus to form phosphorus pentachloride?

Elemental sulfur occurs as octatomic molecules, S8. What mass of fluorine gas is needed to react completely with 17.8 g of sulfur to form sulfur hexafluoride?

Solid iodine trichloride is prepared in two steps: first, a reaction between solid iodine and gaseous chlorine to form solid iodine monochloride; then, treatment with more chlorine. (a) Write a balanced equation for each step. (b)Write a balanced equation for the overall reaction. (c) How many grams of iodine are needed to prepare 2.45 kg of final product?

Lead can be prepared from galena [lead(II) sulfide] by first roasting the galena in oxygen gas to form lead(II) oxide and sulfur dioxide. Heating the metal oxide with more galena forms the molten metal and more sulfur dioxide. (a) Write a balanced equation for each step. (b)Write an overall balanced equation for the process. (c) How many metric tons of sulfur dioxide form for every metric ton of lead obtained?

Many metals react with oxygen gas to form the metal oxide. For example, calcium reacts as follows: 2Ca(s) _ O2(g) 2CaO(s) You wish to calculate the mass of calcium oxide that can be prepared from 4.20 g of Ca and 2.80 g of O2. (a) How many moles of CaO can be produced from the given mass of Ca? (b) How many moles of CaO can be produced from the given mass of O2? (c) Which is the limiting reactant? (d) How many grams of CaO can be produced?

Metal hydrides react with water to form hydrogen gas and the metal hydroxide. For example, SrH2(s) _ 2H2O(l)Sr(OH)2(s) _ 2H2(g) You wish to calculate the mass of hydrogen gas that can be prepared from 5.70 g of SrH2 and 4.75 g of H2O. (a) How many moles of H2 can be produced from the given mass of SrH2? (b) How many moles of H2 can be produced from the given mass of H2O? (c) Which is the limiting reactant? (d) How many grams of H2 can be produced?

Calculate the maximum numbers of moles and grams of iodic acid (HIO3) that can form when 635 g of iodine trichloride reacts with 118.5 g of water: ICl3 _ H2O ICl _ HIO3 _ HCl [unbalanced] What mass of the excess reactant remains?

Calculate the maximum numbers of moles and grams of H2S that can form when 158 g of aluminum sulfide reacts with 131 g of water: Al2S3 _ H2O Al(OH)3 _ H2S [unbalanced] What mass of the excess reactant remains?

When 0.100 mol of carbon is burned in a closed vessel with 8.00 g of oxygen, how many grams of carbon dioxide can form? Which reactant is in excess, and how many grams of it remain after the reaction?

Amixture of 0.0375 g of hydrogen and 0.0185 mol of oxygen in a closed container is sparked to initiate a reaction. How many grams of water can form? Which reactant is in excess, and how many grams of it remain after the reaction?

Aluminum nitrite and ammonium chloride react to form aluminum chloride, nitrogen, and water. What mass of each substance is present after 72.5 g of aluminum nitrite and 58.6 g of ammonium chloride react completely?

Calcium nitrate and ammonium fluoride react to form calcium fluoride, dinitrogen monoxide, and water vapor. What mass of each substance is present after 16.8 g of calcium nitrate and 17.50 g of ammonium fluoride react completely?

Two successive reactions, A B and B C, have yields of 73% and 68%, respectively. What is the overall percent yield for conversion of A to C?

Two successive reactions, D E and E F, have yields of 48% and 73%, respectively. What is the overall percent yield for conversion of D to F?

What is the percent yield of a reaction in which 45.5 g of tungsten(VI) oxide (WO3) reacts with excess hydrogen gas to produce metallic tungsten and 9.60 mL of water (d _ 1.00 g/mL)?

What is the percent yield of a reaction in which 200. g of phosphorus trichloride reacts with excess water to form 128 g of HCl and aqueous phosphorous acid (H3PO3)?

When 20.5 g of methane and 45.0 g of chlorine gas undergo a reaction that has a 75.0% yield, what mass of chloromethane (CH3Cl) forms? Hydrogen chloride also forms.

When 56.6 g of calcium and 30.5 g of nitrogen gas undergo a reaction that has a 93.0% yield, what mass of calcium nitride forms?

Cyanogen, (CN)2, has been observed in the atmosphere of Titan, Saturns largest moon, and in the gases of interstellar nebulas. On Earth, it is used as a welding gas and a fumigant. In its reaction with fluorine gas, carbon tetrafluoride and nitrogen trifluoride gases are produced. What mass of carbon tetrafluoride forms when 60.0 g of each reactant is used?

Gaseous dichlorine monoxide decomposes readily to chlorine and oxygen gases. (a) Which of the following circles best depicts the product mixture after the decomposition? (b) Write the balanced equation for the decomposition. (c) If each oxygen atom represents 0.050 mol, how many molecules of dichlorine monoxide were present before the decomposition?

An intermediate step in the industrial production of nitric acid involves the reaction of ammonia with oxygen gas to form nitrogen monoxide and water. How many grams of nitrogen monoxide can form by the reaction of 485 g of ammonia with 792 g of oxygen?

Butane gas is compressed and used as a liquid fuel in disposable cigarette lighters and lightweight camping stoves. Suppose a lighter contains 5.50 mL of butane (d _ 0.579 g/mL). (a) How many grams of oxygen are needed to burn the butane completely? (b) How many moles of H2O form when all the butane burns? (c) How many total molecules of gas form when the butane burns completely?

Sodium borohydride (NaBH4) is used industrially in many organic syntheses. One way to prepare it is by reacting sodium hydride with gaseous diborane (B2H6). Assuming an 88.5% yield, how many grams of NaBH4 can be prepared by reacting 7.98 g of sodium hydride and 8.16 g of diborane? (Sample Problems 3.15 to 3.20)

Box A represents a unit volume of a solution. Choose from boxes B and C the one representing the same unit volume of solution that has (a) more solute added; (b) more solvent added; (c) higher molarity; (d) lower concentration.

A mathematical equation useful for dilution calculations is Mdil _ Vdil _ Mconc _ Vconc. (a) What does each symbol mean, and why does the equation work? (b) Given the volume and molarity of a CaCl2 solution, how do you determine the number of moles and the mass of solute?

Six different aqueous solutions (with solvent molecules omitted for clarity) are represented in the beakers in the next column, and their total volumes are noted. A B C A B C (a) Which solution has the highest molarity? (b) Which solutions have the same molarity? (c) If you mix solutions Aand C, does the resulting solution have a higher, a lower, or the same molarity as solution B? (d) After 50. mL of water is added to solution D, is its molarity higher, lower, or the same as after 75 mL is added to solution F? (e) How much solvent must be evaporated from solution E for it to have the same molarity as solution A?

Are the following instructions for diluting a 10.0 M solution to a 1.00 M solution correct: Take 100.0 mL of the 10.0 M solution and add 900.0 mL water? Explain.

Calculate each of the following quantities: (a) Grams of solute in 185.8 mL of 0.267 M calcium acetate (b) Molarity of 500. mL of solution containing 21.1 g of potassium iodide (c) Moles of solute in 145.6 L of 0.850 M sodium cyanide

Calculate each of the following quantities: (a) Volume in milliliters of 2.26 M potassium hydroxide that contains 8.42 g of solute (b) Number of Cu2_ ions in 52 L of 2.3 M copper(II) chloride (c) Molarity of 275 mL of solution containing 135 mmol of glucose

Calculate each of the following quantities: (a) Grams of solute needed to make 475 mL of 5.62_10_2 M potassium sulfate (b) Molarity of a solution that contains 7.25 mg of calcium chloride in each milliliter (c) Number of Mg2_ ions in each milliliter of 0.184 M magnesium bromide

Calculate each of the following quantities: (a) Molarity of the solution resulting from dissolving 46.0 g of silver nitrate in enough water to give a final volume of 335 mL (b) Volume in liters of 0.385 M manganese(II) sulfate that contains 63.0 g of solute (c) Volume in milliliters of 6.44_10_2 M adenosine triphosphate (ATP) that contains 1.68 mmol of ATP

Calculate each of the following quantities: (a) Molarity of a solution prepared by diluting 37.00 mL of 0.250 M potassium chloride to 150.00 mL (b) Molarity of a solution prepared by diluting 25.71 mL of 0.0706 M ammonium sulfate to 500.00 mL (c) Molarity of sodium ion in a solution made by mixing 3.58 mL of 0.348 M sodium chloride with 500. mL of 6.81_10_2 M sodium sulfate (assume volumes are additive)

Calculate each of the following quantities: (a) Volume of 2.050 M copper(II) nitrate that must be diluted with water to prepare 750.0 mL of a 0.8543 M solution (b) Volume of 1.63 M calcium chloride that must be diluted with water to prepare 350. mL of a 2.86_10_2Mchloride ion solution (c) Final volume of a 0.0700 M solution prepared by diluting 18.0 mL of 0.155 M lithium carbonate with water

A sample of concentrated nitric acid has a density of 1.41 g/mL and contains 70.0% HNO3 by mass. (a) What mass of HNO3 is present per liter of solution? (b) What is the molarity of the solution?

Concentrated sulfuric acid (18.3 M) has a density of 1.84 g/mL. (a) How many moles of H2SO4 are in each milliliter of solution? (b) What is the mass % of H2SO4 in the solution?

How many milliliters of 0.383 M HCl are needed to react with 16.2 g of CaCO3? 2HCl(aq) _ CaCO3(s) CaCl2(aq) _ CO2(g) _ H2O(l)

How many grams of NaH2PO4 are needed to react with 43.74 mL of 0.285 M NaOH? NaH2PO4(s) _ 2NaOH(aq) Na3PO4(aq) _ 2H2O(l)

How many grams of solid barium sulfate form when 35.0 mL of 0.160 M barium chloride reacts with 58.0 mL of 0.065 M sodium sulfate? Aqueous sodium chloride forms also.

How many moles of excess reactant are present when 350. mL of 0.210 M sulfuric acid reacts with 0.500 L of 0.196 M sodium hydroxide to form water and aqueous sodium sulfate?

Ordinary household bleach is an aqueous solution of sodium hypochlorite. What is the molarity of a bleach solution that contains 20.5 g of sodium hypochlorite in a total volume of 375 mL?

Muriatic acid, an industrial grade of concentrated HCl, is used to clean masonry and cement. Its concentration is 11.7 M. (a) Write instructions for diluting the concentrated acid to make 3.0 gallons of 3.5 M acid for routine use (1 gal _ 4 qt; 1 qt _ 0.946 L). (b) How many milliliters of the muriatic acid solution contain 9.66 g of HCl?

A sample of impure magnesium was analyzed by allowing it to react with excess HCl solution: Mg(s) _ 2HCl(aq) MgCl2(aq) _ H2(g) After 1.32 g of the impure metal was treated with 0.100 L of 0.750 M HCl, 0.0125 mol of HCl remained. Assuming the impurities do not react, what is the mass % of Mg in the sample?

The mole is defined in terms of the carbon-12 atom. Use the definition to find (a) the mass in grams equal to 1 atomic mass unit; (b) the ratio of the gram to the atomic mass unit.

The study of sulfur-nitrogen compounds is an active area of chemical research, made more so by the discovery in the early 1980s of one such compound that conducts electricity like a metal. The first sulfur-nitrogen compound was prepared in 1835 and serves today as a reactant for preparing many of the others. Mass spectrometry of the compound shows a molar mass of 184.27 g/mol, and analysis shows it to contain 2.288 g of S for every 1.000 g of N. What is its molecular formula?

Hydroxyapatite, Ca5(PO4)3(OH), is the main mineral component of dental enamel, dentin, and bone, and thus has many medical uses. Coating it on metallic implants (such as titanium alloys and stainless steels) helps the body accept the implant. In the form of powder and beads, it is used to fill bone voids, which encourages natural bone to grow into the void. Hydroxyapatite is prepared by adding aqueous phosphoric acid to a dilute slurry of calcium hydroxide. (a) Write a balanced equation for this preparation. (b) What mass of hydroxyapatite could form from 100. g of 85% phosphoric acid and 100. g of calcium hydroxide?

Narceine is a narcotic in opium that crystallizes from solution as a hydrate that contains 10.8 mass % water and has a molar mass of 499.52 g/mol. Determine x in narceine_xH2O.

Hydrogen-containing fuels have a fuel value based on their mass % H. Rank the following compounds from highest mass % H to lowest: ethane, propane, benzene, ethanol, cetyl palmitate (whale oil, C32H64O2).

Serotonin (_ _ 176 g/mol) transmits nerve impulses between neurons. It contains 68.2 mass % C, 6.86 mass % H, 15.9 mass % N, and 9.08 mass % O. What is its molecular formula?

In 1961, scientists agreed that the atomic mass unit (amu) would be defined as the mass of an atom of 12C. Before then, it was defined as the average mass of an atom of naturally occurring oxygen (a mixture of 16O, 17O, and 18O). The current atomic mass of oxygen is 15.9994 amu. (a) Did Avogadros number change after the definition of an amu changed and, if so, in what direction? (b) Did the definition of the mole change? (c) Did the mass of a mole of a substance change? (d) Before 1961, was Avogadros number 6.02_1023 (when considered to three significant figures), as it is today?

Convert the following descriptions into balanced equations: (a) In a gaseous reaction, hydrogen sulfide burns in oxygen to form sulfur dioxide and water vapor. (b) When crystalline potassium chlorate is heated to just above its melting point, it reacts to form two different crystalline compounds, potassium chloride and potassium perchlorate. (c) When hydrogen gas is passed over powdered iron(III) oxide, iron metal and water vapor form. (d) The combustion of gaseous ethane in air forms carbon dioxide and water vapor. (e) Iron(II) chloride is converted to iron(III) fluoride by treatment with chlorine trifluoride gas. Chlorine gas is also formed.

Isobutylene is a hydrocarbon used in the manufacture of synthetic rubber. When 0.847 g of isobutylene was analyzed by combustion analysis (see Figure 3.5), the gain in mass of the CO2 absorber was 2.657 g and that of the H2O absorber was 1.089 g. What is the empirical formula of isobutylene?

The multistep smelting of ferric oxide to form elemental iron occurs at high temperatures in a blast furnace. In the first step, ferric oxide reacts with carbon monoxide to form Fe3O4. This substance reacts with more carbon monoxide to form iron(II) oxide, which reacts with still more carbon monoxide to form molten iron. Carbon dioxide is also produced in each step. (a) Write an overall balanced equation for the iron-smelting process. (b) How many grams of carbon monoxide are required to form 45.0 metric tons of iron from ferric oxide?

One of the compounds used to increase the octane rating of gasoline is toluene (right). Suppose 20.0 mL of toluene (d _ 0.867 g/mL) is consumed when a sample of gasoline burns in air. (a) How many grams of oxygen are needed for complete combustion of the toluene? (b) How many total moles of gaseous products form? (c) How many molecules of water vapor form?

During studies of the reaction in Sample Problem 3.13, 2N2H4(l) _ N2O4(l) 3N2(g) _ 4H2O(g) a chemical engineer measured a less-than-expected yield of N2 and discovered that the following side reaction occurs: N2H4(l) _ 2N2O4(l) 6NO(g) _ 2H2O(g) In one experiment, 10.0 g of NO formed when 100.0 g of each reactant was used. What is the highest percent yield of N2 that can be expected?

A 0.652-g sample of a pure strontium halide reacts with excess sulfuric acid, and the solid strontium sulfate formed is separated, dried, and found to weigh 0.755 g. What is the formula of the original halide?

The following circles represent a chemical reaction between AB2 and B2: (a) Write a balanced equation for the reaction. (b) What is the limiting reactant? (c) How many moles of product can be made from 3.0 mol of B2 and 5.0 mol of AB2? (d) How many moles of excess reactant remain after the reaction in part (c)?

Calculate each of the following quantities: (a) Volume of 18.0 M sulfuric acid that must be added to water to prepare 2.00 L of a 0.429 M solution (b) Molarity of the solution obtained by diluting 80.6 mL of 0.225 M ammonium chloride to 0.250 L (c) Volume of water added to 0.130 L of 0.0372 M sodium hydroxide to obtain a 0.0100 M solution (assume the volumes are additive at these low concentrations) (d) Mass of calcium nitrate in each milliliter of a solution prepared by diluting 64.0 mL of 0.745 M calcium nitrate to a final volume of 0.100 L

A student weighs a sample of carbon on a balance that is accurate to _0.001 g. (a) How many atoms are in 0.001 g of C? (b) The carbon is used in the following reaction: Pb3O4(s) _ C(s) 3PbO(s) _ CO(g) What mass difference in the lead(II) oxide would be caused by an error in the carbon mass of 0.001 g?

The zirconium oxalate K2Zr(C2O4)3(H2C2O4)_H2O was synthesized by mixing 1.68 g of ZrOCl2_8H2O with 5.20 g of H2C2O4_2H2O and an excess of aqueous KOH. After 2 months, 1.25 g of crystalline product was obtained, as well as aqueous KCl and water. Calculate the percent yield.

Seawater is approximately 4.0% by mass dissolved ions. About 85% of the mass of the dissolved ions is from NaCl. (a) Find the mass % of NaCl in seawater. (b) Find the mass % of Na_ ions and of Cl_ ions in seawater. (c) Find the molarity of NaCl in seawater at 15_C (d of seawater at 15_C _ 1.025 g/mL).

Is each of the following statements true or false? Correct any that are false: (a) A mole of one substance has the same number of atoms as a mole of any other substance. (b) The theoretical yield for a reaction is based on the balanced chemical equation. (c) A limiting-reactant problem is presented when the quantity of available material is given in moles for one of the reactants. (d) To prepare 1.00 L of 3.00 M NaCl, weigh 175.5 g of NaCl and dissolve it in 1.00 L of distilled water. (e) The concentration of a solution is an intensive property, but the amount of solute in a solution is an extensive property.

Box A represents one unit volume of solution A. Which boxB, C, or Drepresents one unit volume after adding enough solvent to solution A to (a) triple its volume; (b) double its volume; (c) quadruple its volume?

In each pair, choose the larger of the indicated quantities or state that the samples are equal: (a) Entities: 0.4 mol of O3 molecules or 0.4 mol of O atoms (b) Grams: 0.4 mol of O3 molecules or 0.4 mol of O atoms (c) Moles: 4.0 g of N2O4 or 3.3 g of SO2 (d) Grams: 0.6 mol of C2H4 or 0.6 mol of F2 (e) Total ions: 2.3 mol of sodium chlorate or 2.2 mol of magnesium chloride (f) Molecules: 1.0 g of H2O or 1.0 g of H2O2 (g) Na_ ions: 0.500 L of 0.500 M NaBr or 0.0146 kg of NaCl (h) Mass: 6.02_1023 atoms of 235U or 6.02_1023 atoms of 238U

For the reaction between solid tetraphosphorus trisulfide and oxygen gas to form solid tetraphosphorus decaoxide and sulfur dioxide gas, write a balanced equation. Show the equation (see Table 3.5) in terms of (a) molecules, (b) moles, and (c) grams.

Hydrogen gas has been suggested as a clean fuel because it produces only water vapor when it burns. If the reaction has a 98.8% yield, what mass of hydrogen forms 105 kg of water?

Assuming that the volumes are additive, what is the concentration of KBr in a solution prepared by mixing 0.200 L of 0.053 M KBr with 0.550 L of 0.078 M KBr?

Solar winds composed of free protons, electrons, and particles bombard Earth constantly, knocking gas molecules out of the atmosphere. In this way, Earth loses about 3.0 kg of matter per second. It is estimated that the atmosphere will be gone in about 50 billion years. Use this estimate to calculate (a) the mass (kg) of Earths atmosphere and (b) the amount (mol) of nitrogen, which makes up 75.5 mass % of the atmosphere.

Calculate each of the following quantities: (a) Moles of compound in 0.588 g of ammonium bromide (b) Number of potassium ions in 88.5 g of potassium nitrate (c) Mass in grams of 5.85 mol of glycerol (C3H8O3) (d) Volume of 2.85 mol of chloroform (CHCl3; d _ 1.48 g/mL) (e) Number of sodium ions in 2.11 mol of sodium carbonate (f) Number of atoms in 25.0 g of cadmium (g) Number of atoms in 0.0015 mol of fluorine gas

Elements X (green) and Y (purple) react according to the following equation: X2 _ 3Y2 2XY3. Which molecular scene represents the product of the reaction?

Hydrocarbon mixtures are used as fuels. (a) How many grams of CO2(g) are produced by the combustion of 200. g of a mixture that is 25.0% CH4 and 75.0% C3H8 by mass? (b) A252-g gaseous mixture of CH4 and C3H8 burns in excess O2, and 748 g of CO2 gas is collected. What is the mass % of CH4 in the mixture?

To 1.35 L of 0.325 M HCl, you add 3.57 L of a second HCl solution of unknown concentration. The resulting solution is 0.893 M HCl. Assuming the volumes are additive, calculate the molarity of the second HCl solution.

Nitrogen (N), phosphorus (P), and potassium (K) are the main nutrients in plant fertilizers. By industry convention, the numbers on the label refer to the mass percents of N, P2O5, and K2O, in that order. Calculate the N/P/K ratio of a 30/10/10 fertilizer in terms of moles of each element, and express it as x/y/1.0.

What mass % of ammonium sulfate, ammonium hydrogen phosphate, and potassium chloride would you use to prepare 10/10/10 plant fertilizer (see Problem 3.140)?

Methane and ethane are the two simplest hydrocarbons. What is the mass % C in a mixture that is 40.0% methane and 60.0% ethane by mass?

Ferrocene, synthesized in 1951, was the first organic iron compound with Fe C bonds. An understanding of the structure of ferrocene gave rise to new ideas about chemical bonding and led to the preparation of many useful compounds. In the combustion analysis of ferrocene, which contains only Fe, C, and H, a 0.9437-g sample produced 2.233 g of CO2 and 0.457 g of H2O. What is the empirical formula of ferrocene?

When carbon-containing compounds are burned in a limited amount of air, some CO(g) as well as CO2(g) is produced. A gaseous product mixture is 35.0 mass % CO and 65.0 mass % CO2. What is the mass % C in the mixture?

Write a balanced equation for the reaction depicted below: If each reactant molecule represents 1.25_10_2 mol and the reaction yield is 87%, how many grams of Si-containing product form?

Citric acid (right) is concentrated in citrus fruits and plays a central metabolic role in nearly every animal and plant cell. (a) What are the molar mass and formula of citric acid? (b) How many moles of citric acid are in 1.50 qt of lemon juice (d _ 1.09 g/mL) that is 6.82% citric acid by mass?

Various nitrogen oxides, as well as sulfur oxides, contribute to acidic rainfall through complex reaction sequences. Nitrogen and oxygen combine during high-temperature combustion of fuels in air to form nitrogen monoxide gas, which reacts with more oxygen to form nitrogen dioxide gas. In contact with water vapor, nitrogen dioxide forms aqueous nitric acid and more nitrogen monoxide. (a) Write balanced equations for these reactions. (b) Use the equations to write one overall balanced equation that does not include nitrogen monoxide and nitrogen dioxide. (c) How many metric tons (t) of nitric acid form when 1350 t of atmospheric nitrogen is consumed (1 t _ 1000 kg)?

Alum [KAl(SO4)2_xH2O] is used in food preparation, dye fixation, and water purification. To prepare alum, aluminum is reacted with potassium hydroxide and the product with sulfuric acid. Upon cooling, alum crystallizes from the solution. (a) A 0.5404-g sample of alum is heated to drive off the waters of hydration, and the resulting KAl(SO4)2 weighs 0.2941 g. Determine the value of x and the complete formula of alum. (b) When 0.7500 g of aluminum is used, 8.500 g of alum forms. What is the percent yield?

Nitrogen monoxide reacts with elemental oxygen to form nitrogen dioxide. The scene at right represents an initial mixture of reactants. If the reaction has a 66% yield, which of the scenes below (A, B, or C) best represents the final product mixture?

When 1.5173 g of an organic iron compound containing Fe, C, H, and O was burned in O2, 2.838 g of CO2 and 0.8122 g of H2O were produced. In a separate experiment to determine the mass % of iron, 0.3355 g of the compound yielded 0.0758 g of Fe2O3. What is the empirical formula of the compound?

Fluorine is so reactive that it forms compounds with materials inert to other treatments. (a) When 0.327 g of platinum is heated in fluorine, 0.519 g of a dark red, volatile solid forms. What is its empirical formula? (b) When 0.265 g of this red solid reacts with excess xenon gas, 0.378 g of an orange-yellow solid forms. What is the empirical formula of this compound, the first to contain a noble gas? (c) Fluorides of xenon can be formed by direct reaction of the elements at high pressure and temperature. Under conditions that produce only the tetra- and hexafluorides, 1.85_10_4 mol of xenon reacted with 5.00_10_4 mol of fluorine, and 9.00_10_6 mol of xenon was found in excess. What are the mass percents of each xenon fluoride in the product mixture?

Hemoglobin is 6.0% heme (C34H32FeN4O4) by mass. To remove the heme, hemoglobin is treated with acetic acid and NaCl to form hemin (C34H32N4O4FeCl). At a crime scene, a blood sample contains 0.65 g of hemoglobin. (a) How many grams of heme are in the sample? (b) How many moles of heme? (c) How many grams of Fe? (d) How many grams of hemin could be formed for a forensic chemist to measure?

Manganese is a key component of extremely hard steel. The element occurs naturally in many oxides. A 542.3-g sample of a manganese oxide has an Mn/O ratio of 1.00/1.42 and consists of braunite (Mn2O3) and manganosite (MnO). (a) What masses of braunite and manganosite are in the ore? (b) What is the ratio Mn3_/Mn2_ in the ore?

Sulfur dioxide is a major industrial gas used primarily for the production of sulfuric acid, but also as a bleach and food preservative. One way to produce it is by roasting iron pyrite (iron disulfide, FeS2) in oxygen, which yields the gas and solid iron(III) oxide. What mass of each of the other three substances is involved in producing 1.00 kg of sulfur dioxide?

The human body excretes nitrogen in the form of urea, NH2CONH2. The key biochemical step in urea formation is the reaction of water with arginine to produce urea and ornithine: (a) What is the mass percent of nitrogen in urea, arginine, and ornithine? (b) How many grams of nitrogen can be excreted as urea when 135.2 g of ornithine is produced?

Aspirin (acetylsalicylic acid, C9H8O4) is made by reacting salicylic acid (C7H6O3) with acetic anhydride [(CH3CO)2O]: C7H6O3(s) _ (CH3CO)2O(l) C9H8O4(s) _ CH3COOH(l) In one reaction, 3.077 g of salicylic acid and 5.50 mL of acetic anhydride react to form 3.281 g of aspirin. (a) Which is the limiting reactant (d of acetic anhydride _ 1.080 g/mL)? (b) What is Arginine Water Urea Ornithine + + N H C O + + + + the percent yield of this reaction? (c) What is the percent atom economy of this reaction?

The rocket fuel hydrazine (N2H4) is made by the three-step Raschig process, which has the following overall equation: NaOCl(aq) _ 2NH3(aq) N2H4(aq) _ NaCl(aq) _ H2O(l) What is the percent atom economy of this process?

Lead(II) chromate (PbCrO4) is used as the yellow pigment in traffic lanes, but is banned from house paint because of the risk of lead poisoning. It is produced from chromite (FeCr2O4), an ore of chromium: 4FeCr2O4(s) _ 8K2CO3(aq) _ 7O2(g) 2Fe2O3(s) _ 8K2CrO4(aq) _ 8CO2(g) Lead(II) ion then replaces the K_ ion. If a yellow paint is 0.511% PbCrO4 by mass, how many grams of chromite are needed per kilogram of paint?

Ethanol (CH3CH2OH), the intoxicant in alcoholic beverages, is also used to make other organic compounds. In concentrated sulfuric acid, ethanol forms diethyl ether and water: 2CH3CH2OH(l) CH3CH2OCH2CH3(l) _ H2O(g) In a side reaction, some ethanol forms ethylene and water: CH3CH2OH(l) CH2 CH2(g) _ H2O(g) (a) If 50.0 g of ethanol yields 35.9 g of diethyl ether, what is the percent yield of diethyl ether? (b) During the process, 45.0% of the ethanol that did not produce diethyl ether reacts by the side reaction. What mass of ethylene is produced?

When powdered zinc is heated with sulfur, a violent reaction occurs, and zinc sulfide forms: Zn(s) _ S8(s) ZnS(s) [unbalanced] Some of the reactants also combine with oxygen in air to form zinc oxide and sulfur dioxide. When 83.2 g of Zn reacts with 52.4 g of S8, 104.4 g of ZnS forms. What is the percent yield of ZnS? (b) If all the remaining reactants combine with oxygen, how many grams of each of the two oxides form?

Cocaine (C17H21O4N) is a natural substance found in coca leaves, which have been used for centuries as a local anesthetic and stimulant. Illegal cocaine arrives in the United States either as the pure compound or as the hydrochloride salt (C17H21O4NHCl). At 25_C, the salt is very soluble in water (2.50 kg/L), but cocaine is much less so (1.70 g/L). (a) What is the maximum amount (in g) of the salt that can dissolve in 50.0 mL of water? (b) If the solution in part (a) is treated with NaOH, the salt is converted to cocaine. How much additional water (in L) is needed to dissolve it?

High-temperature superconducting oxides hold great promise in the utility, transportation, and computer industries. (a) One superconductor is La2_xSrxCuO4. Calculate the molar masses of this oxide when x _ 0, x _ 1, and x _ 0.163. (b) Another common superconducting oxide is made by heating a mixture of barium carbonate, copper(II) oxide, and yttrium(III) oxide, followed by further heating in O2: 4BaCO3(s) _ 6CuO(s) _ Y2O3(s) 2YBa2Cu3O6.5(s) _ 4CO2(g) 2YBa2Cu3O6.5(s) _ O2(g) 2YBa2Cu3O7(s) When equal masses of the three reactants are heated, which reactant is limiting? (c) After the product in part (b) is removed, what is the mass percent of each reactant in the remaining solid mixture?