40.25% C, 6.19% H, 8.94% O, and 44.62% Br. What is its

PROBLEM 1QP Match the key terms with the descriptions provided. (a) the amount of a substance that contains the same number of atoms, molecules, or formula units as there are atoms in exactly 12 g of carbon-12 (12C) (b) the number of fundamental particles (atoms, molecules, or ions) in 1 mol of any substance (c) a formula written with the simplest ratios of atoms or ions (the smallest whole-number subscripts) (d) the substance being dissolved; usually, that component of a solution that is present in the lesser amount (e) the number of moles of solute per liter of solution (f) a solution that contains a relatively high concentration of solute

PROBLEM 5QP Flonase nasal spray contains a steroid drug used to treat allergies. The dose from one spray of the dispenser contains 50.0 ?g of active ingredient, in which there is 30.0 ?g of carbon. What is the percent carbon in the active ingredient for Flonase?

PROBLEM 3QP A 24.7-g sample of limestone, CaCO3, contains 9.88 g of calcium. What is the percent Ca in limestone?

PROBLEM 2QP Match the key terms with the descriptions provided. (a) the mass of 1 mol of any substance, in units of grams per mole (b) an expression of the percent of the total mass due to each element in a compound (c) the substance doing the dissolving; usually, that component of a solution that is present in the larger amount (d) the relative amounts of solute and solvent in a solution (e) a solution that contains a relatively small concentration of solute (f) the process of adding more solvent to give a solution of lesser concentration

PROBLEM 4QP A 3.75-g sample of limestone, CaCO3, contains 1.80 g of oxygen and 0.450 g of carbon. What is the percent O and the percent C in limestone?

PROBLEM 130QP If 4.32 g of Cu combines with 1.09 g of S to form 5.41 g of the bluish-black mineral chalcocite, what is the empirical formula of chalcocite?

PROBLEM 6QP In addition to its more well-known use, Viagra has been shown to be effective in treating a rare pulmonary disorder. A 20.0-mg dose of the drug, sold as Revatio, contains 3.54 mg of nitrogen. What is the percent nitrogen in Revatio?

PROBLEM 8QP Quartz, SiO2, contains 46.7% silicon. What mass of silicon is present in 348 g of quartz?

PROBLEM 9QP Write the formulas for the compounds described by the following compositions. (a) twice as many hydrogen atoms as sulfur atoms (b) 1.5 times as many oxygen atoms as nitrogen atoms (c) one-half as many calcium ions as chloride ions

PROBLEM 7QP Lithium carbonate, Li2CO3, contains 18.8% lithium and is used in the treatment of mental illnesses such as bipolar disorder. What mass of lithium is present in a 1.20-g dose of lithium carbonate?

PROBLEM 10QP Write the formulas for the compounds described by the following compositions. (a) three times as many hydrogen atoms as phosphorus atoms (b) 2.5 times as many oxygen atoms as nitrogen atoms (c) one-third as many aluminum ions as chlorate ions

PROBLEM 111QP Determine the concentrations of the following diluted solutions. (a) 24.75 mL of 0.1832 M HCl diluted to 250.0 mL (b) 125 mL of 1.187 M NaOH diluted to 0.500 L (c) 10.00 mL of 0.2010 M acetic acid, CH3CO2H, diluted to 50.00 mL

PROBLEM 12QP What are the formulas of the following molecules?

PROBLEM 13QP What is the molecular formula of these molecules?

PROBLEM 14QP What is the molecular formula of these molecules?

PROBLEM 15QP What are the formula units for each of the following?

PROBLEM 17QP How many NH3 molecules are in 0.50 mol of NH3? How many nitrogen atoms and hydrogen atoms are there?

PROBLEM 16QP What are the formula units for each of the following?

PROBLEM 18QP How many SO2 molecules are in 1.75 mol of SO2? How many sulfur atoms and oxygen atoms are there?

PROBLEM 19QP How many formula units are in 0.5 mol of Cu2S?

PROBLEM 20QP How many formula units are in 1.5 mol of CuSO4?

PROBLEM 21QP How many sulfur atoms are in 0.2 mol of SO2?

PROBLEM 22QP How many oxygen atoms are in 0.2 mol of SO2?

PROBLEM 24QP How many chloride ions are in 2 mol of CaCl2?

PROBLEM 23QP How many calcium ions are in 1 mol of CaCl2?

PROBLEM 25QP Calculate the molar mass of the substances shown in Question 4.15. Reference Question 4.15: What are the formula units for each of the following?

PROBLEM 26QP Calculate the molar mass of the substances shown in Question 4.16. Reference Question 4.16: What are the formula units for each of the following?

PROBLEM 27QP Calculate the molar mass of each of the following compounds. 1. Hg2Cl2 (c) Cl2O5 2. CaSO4 2H2O (d) NaHSO4

PROBLEM 28QP Calculate the molar mass of each of the following compounds. 1. K2SO4 (c) C2H4Cl2 2. NiCl2 6H2O (d) Mg(NO3)2

PROBLEM 31QP In general, why must we weigh a sample in order to determine the number of atoms it contains?

PROBLEM 29QP Calculate the molar mass of the following substances. 1. I2 (b) CrCl2 (c) C4H8

PROBLEM 30QP Calculate the molar mass of the following substances. 1. P4 (b) CrO2Cl2 (c) CaF2

PROBLEM 32QP What is a mole? Why do chemists need to use the concept?

PROBLEM 33QP If 1.00 mol of LiCl has a mass of 42.394 g, what is the average mass of 1 LiCl formula unit in atomic mass units?

PROBLEM 34QP If one formula unit of CuCl2 has an average mass of 134.5 amu, what is the mass of 1.00 mol of CuCl2?

PROBLEM 37QP Calculate the number of moles in 10.0 g of the following substances. 1. KHCO3 (c) Se 2. H2S (d) MgSO4

PROBLEM 38QP Calculate the number of moles in 100.0 g of each of the following compounds. 1. SO2 (c) BaSO4 2. Na2SO4 (d) KAI(SO4)2

PROBLEM 35QP If 2.01 ×1023 molecules of a substance have a mass of 12.0 g, what is the molar mass of the substance?

PROBLEM 36QP If the molar mass of a substance is 98.09 g/mol, what is the mass of 3.01 ×1023 molecules of the substance?

PROBLEM 39QP Calculate the moles of the following substances. 1. 32.5 g NaCl (c) 73.4 kg CaCO3 2. 250.0 mg aspirin, (d) 5.47 g CuS C9HgO4

PROBLEM 40QP Calculate the moles of the following substances. 1. 72.2 g K2SO4 (c) 2.82 g magnetite, Fe3O4 1. 160.0 mg oxycodone, (d)5.00 g sucrose, C18H21NO4 C12H22O11

PROBLEM 41QP Which element, Mo, Se, Na, or Br, contains the most moles of atoms in a 1.0-g sample?

PROBLEM 42QP Which element, Cu, P, Ag, or B, contains the least moles of atoms in a 5.0-g sample?

PROBLEM 43QP Calculate the mass of 2.50 mol of the following substances. 1. BA(OH)2 (c) K2SO4 2. Cl2 (d) PF3

PROBLEM 44QP Calculate the mass of 0.750 mol of the following substances. 1. I2 (c) SiO2 2. Mg(NO3)2 (d) Na3PO4

PROBLEM 45QP A chemical reaction requires 2.7 mol of zinc acetate, Zn(CH3CO2)2. What mass of zinc acetate is needed?

PROBLEM 46QP A chemical reaction is used to produce 3.4 mol of copper(II) bicarbonate, Cu(HCO3)2. What mass of copper(II) bicarbonate is produced?

PROBLEM 47QP A sample of ammonia, NH3, weighs 30.0 g. Calculate the following quantities. 1. moles of NH3 (c) number of N atoms 2. number of NH3 (d) moles of H atoms molecules

PROBLEM 49QP Which of these substances has the most atoms per mole? Which has the least?

PROBLEM 50QP Which of these substances has the most atoms per mole? Which has the least?

PROBLEM 48QP A sample of sodium carbonate, Na2CO3, weighs 15.0 g. Calculate the following quantities. 1. moles of Na2CO3 (c) number of Na+ ions 2. number of Na2CO3 (d) moles of CO32- ions Formula units

PROBLEM 51QP A raindrop weighs 0.050 g. How many molecules of water are in one raindrop?

PROBLEM 52QP A grain of sand weighs 7.7 ×10–4 g. How many formula units of silicon dioxide, SiO2, are in one sand grain?

PROBLEM 53QP How many formula units are in 250.0 g of the following substances? 1. Br2 (c) H2O 2. MgCl2 (d) Fe

PROBLEM 54QP How many formula units are in 375.0 g of the following substances? 1. Cu (c) SO2 2. NaBr (d) NH4Cl

PROBLEM 55QP How many atoms (or ions) of each element are in 140.0 g of the following substances? 1. H2 (c) N2O2 2. Ca(NO3)2 (d) K2SO4

PROBLEM 57QP What is the mass of 6.4 ×1022 molecules of SO2?

PROBLEM 58QP What is the mass of 1.8 × 1021 molecules of H2SO4?

PROBLEM 56QP How many atoms (or ions) of each element are in 140.0 g of the following substances? 1. BaSO4 (c) O2 2. Mg3(PO4)2 (d) KBr

PROBLEM 59QP Which compound, NH3, NH4Cl, NO2, or N2O3, contains the most nitrogen atoms in a 25.0-g sample?

PROBLEM 60QP Which compound, NaCl, PCl3, CaCl2, or HClO2, contains the most chlorine atoms (or ions) in a 100.0-g sample?

PROBLEM 61QP You have two colorless gases, each made of sulfur and oxygen. If they have different percent compositions, can they be the same substance?

PROBLEM 62QP Describe some uses for the percent composition of a substance.

PROBLEM 63QP What is the difference between an empirical formula and a molecular formula?

PROBLEM 65QP Which of the following molecules have an empirical formula that is different from their molecular formula?

PROBLEM 64QP Why do we normally use an empirical formula instead of percent composition to represent the composition of a substance?

PROBLEM 66QP Which of the following substances have an empirical formula that is the same as their molecular formula?

PROBLEM 67QP What is the empirical formula of each of the following compounds? 1. P4O10 (c) PbCl4 2. Cl2O5 (d) HO2CC4H8CO2H

PROBLEM 68QP What is the empirical formula of each of the following compounds? 1. As4O6 (c) CaCl2 2. H2S2 (d) C3H6

PROBLEM 69QP Given the following molecular formulas, write the empirical formulas. 1. CHCl2 (b) C6H5Cl (c) N2O5

PROBLEM 70QP Given the following molecular formulas, write the empirical formulas. 1. N2O4 (b) H2C2O4 (c) CH3CO2H

PROBLEM 71QP Which of the following compounds of nitrogen and oxygen have identical empirical formulas: N2O, NO, NO2, N2O3, N2O4, N2O5?

PROBLEM 75QP Eugenol, a chemical substance with the flavor of cloves, consists of 73.19% C, 19.49% O, and 7.37% H. What is the empirical formula of eugenol?

PROBLEM 74QP What are the empirical formulas of the compounds with the following compositions? 1. 85.62% C, 14.38% H 2. 63.15% , 5.30% H, 31.55% O

PROBLEM 72QP Which of the following compounds of carbon and hydrogen have identical empirical formulas: CH4, C2H4, C3H6, C4H12, C6H6?

PROBLEM 76QP One of the compounds in cement has the following composition: 52.66% Ca, 12.30% Si, and 35.04% O. What is its empirical formula?

PROBLEM 77QP The explosive trinitrotoluene (TNT) has the composition 37.01% C, 2.22% H, 18.50% N, and 42.27% O. What is the empirical formula of TNT?

PROBLEM 78QP Strychnine (rat poison) has the composition 75.42% C, 6.63% H, 8.38% N, and 9.57% O. What is the empirical formula of strychnine?

PROBLEM 79QP What information is needed to determine a molecular formula?

PROBLEM 73QP What are the empirical formulas of the compounds with the following compositions? 1. 72.36% Fe, 27.64% O 2. 58.53% C, 4.09% H, 11.38% N, 25.99% O

PROBLEM 80QP In what way does a molecular formula represent more information than an empirical formula?

PROBLEM 82QP A gaseous compound has the empirical formula NO2. If its molar mass is approximately 92 g/mol, what is its molecular formula?

PROBLEM 81QP A compound with the empirical formula CH2O has a molar mass of approximately 90 g/mol. What is its molecular formula?

PROBLEM 83QP A compound has a molar mass of approximately 180 g/mol and a percent composition of 40.00% C, 6.72% H, and 53.29% O. What is the molecular formula?

PROBLEM 84QP A compound with the molar mass of approximately 142 g/mol has the composition 50.7% C, 9.9% H, and 39.4% N. What is its molecular formula?

PROBLEM 85QP What is the percent composition of each of the following compounds? 1. SO2 (b) CuCl2 (c) Na3PO4 (d) Mg(NO3)2

PROBLEM 88QP Calculate the percent iron in the following iron minerals, which might be found in iron ores. Which contains the highest percentage of iron? 1. Wustite (c) magnetite, Fe3O4 2. Hematite, Fe2O3 (d) siderite, FeCO3

PROBLEM 86QP What is the percent nitrogen in each of the following compounds? 1. NaNO3 (b) NH4Cl (c) N2H4 (d) N2O

PROBLEM 87QP Consider the following minerals as potential sources of copper metal. Which mineral contains the highest percentage of copper? 1. Chalcocite, Cu2S (c) cuprite, CuO 2. Malachite, (d) azurite, Cu3(CO3)2(OH)2 Cu2(CO3)(OH)2

PROBLEM 89QP What is a solution? Give five examples of solutions that can be found in your home or dorm.

PROBLEM 90QP Distinguish between a solute and a solvent. Identify the solute in five solutions that can be found in a grocery store.

PROBLEM 91QP Identify the solute and solvent in this solution containing calcium chloride and water. Explain your answer.

PROBLEM 92QP Identify the solute and solvent in this solution containing sodium chloride and water. Explain your answer.

PROBLEM 94QP Give an example of two solutions that could be described as dilute and concentrated.

PROBLEM 93QP What is the difference between a dilute and a concentrated solution?

PROBLEM 95QP What relationship is described by concentration?

PROBLEM 96QP Define molarity.

PROBLEM 97QP Which of the following solutions of NaCl is more concentrated?

PROBLEM 98QP Which of the following solutions of CaCl2 is more dilute?

PROBLEM 99QP Calculate the molarity of each of the following solutions. 1. 122 g of acetic acid, CH3CO2H, in 1.00L of solution 2. 185 g of sucrose, CHO, in 1.00 L of solution 3. 70.0 g hydrogen chloride, HCl, in 0.600 L of solution 4. 45.0 g of potassium hydroxide, KOH, in 250.0 mL of solution

PROBLEM 100QP Calculate the molarity of each of the following solutions. (a) 6.30 g HNO3 dissolved in 255 mL of solution (b) 49.0 g H2SO4 dissolved in 125 mL of solution (c) 2.80 g KOH dissolved in 525 mL of solution (d) 7.40 g Ca(OH)2 dissolved in 200.0 mL of solution

PROBLEM 102QP How many moles of Mg(NO3)2 are present in 225.0 mL of a 1.20 M solution? How many moles of Mg2+ ions are present? How many moles of NO3- ions are present?

PROBLEM 101QP How many moles of Na2SO4 are present in 150.0 mL of a 0.124 M solution? How many moles of Na+ ions are present? How many moles of SO42- ions are present?

PROBLEM 103QP Calculate the moles and the mass of solute in each of the following solutions. (a) 250.0 mL of 1.50 M KCl (b) 250.0 mL of 2.05 M Na2SO4

PROBLEM 104QP Calculate the moles and the mass of solute in each of the following solutions. (a) 150.0 mL of 0.245 M CaCl2 (b) 1450 mL of 0.00187 M H2SO4

PROBLEM 105QP Calculate what volume of the following solutions is required to obtain 0.250 mol of each solute. (a) 0.250 M AlCl3 (b) 3.00 M HCl

PROBLEM 106QP Calculate what volume of the following solutions is required to obtain 0.250 mol of each solute. (a) 1.50 M H2SO4 (b) 0.750 M NaCl

PROBLEM 107QP How much water had to be added to 10.0 mL of the first solution to obtain the second solution?

PROBLEM 108QP How much water had to be added to 50.0 mL of the first solution to obtain the second solution?

PROBLEM 109QP How much water must be added to 935.0 mL of 0.1074 M HCl to obtain a solution that is exactly 0.1000 M?

PROBLEM 111QP Determine the concentrations of the following diluted solutions. (a) 24.75 mL of 0.1832 ?M H ? Cl diluted to 250.0 mL (b) 125 mL of 1.187 ?M ?NaOH diluted to 0.500 L (c) 10.00 mL of 0.2010 M ? ?acetic acid, CH3CO2H, diluted to 50.00 mL

PROBLEM 110QP If you wish to prepare a 0.055 M solution of NaNO3, to what volume would you have to dilute 25 mL of 3.0 M NaNO3?

PROBLEM 112QP Determine the concentrations of the following diluted solutions. (a) 35.45 mL of 6.00 M KOH diluted to 150.0 mL (b) 250.0 mL of 0.00102 M NH3 diluted to 500.0 mL (c) 5.00 mL of 0.8045 M CaCl2 diluted to 250.00 mL

PROBLEM 113QP What is the mass of 0.100 mol of Cu(OH)2?

PROBLEM 114QP How many (a) moles, (b) grams, and (c) atoms of vanadium are in 52.5 g of V2O5?

PROBLEM 115QP What is the average mass of one atom of argon in atomic mass units and in units of grams?

PROBLEM 116QP How many molecules are present in 15.43 g of butyl alcohol, C4H9OH?

PROBLEM 117QP Calculate the number of moles of atoms and the number of atoms in the following quantities. (a) 36.1 g of argon (b) the 44.5-carat Hope diamond, which consists of carbon (1 carat = 0.200 g) (c) 2.50 mL of mercury with a density of 13.6 g/mL

PROBLEM 118QP What mass of iodine contains the same number of atoms as 50.0 g of chlorine?

PROBLEM 120QP A gaseous compound has the composition 92.3% C and 7.7% H by mass. What is its empirical formula? If the molar mass of the compound is 78.1 g/mol, what is its molecular formula?

PROBLEM 121QP Tear gas has the composition 40.25% C, 6.19% H, 8.94% O, and 44.62% Br. What is its empirical formula?

PROBLEM 119QP Calcium carbonate is the active ingredient in some antacids. It is also the compound in the mineral known as calcite. How many moles of calcium carbonate are present in a chewable table that contains 750.0 mg CaCO3?

PROBLEM 122QP A chemical procedure calls for 3.54 mol of dry ice (solid CO2). What mass of CO2 should we add?

PROBLEM 123QP How many oxygen atoms are contained in 10.00 g of H3PO4?

PROBLEM 124QP Calculate the mass percent of each element in Na2CO3.

PROBLEM 125QP How many molecules of CO2 are contained in the 960 g of CO2 exhaled daily by an average person?

PROBLEM 126QP The formula for ibuprofen is C13H18O2. How many moles of ibuprofen are present in a 200.0-mg tablet?

PROBLEM 127QP Vanillin, the active component of the flavoring vanilla, has the composition 63.15% C, 5.30% H, and 31.55% O. (a) What is its empirical formula? (b) If the molar mass of vanillin is 152.14 g/mol, what is its molecular formula?

PROBLEM 128QP Monosodium glutamate, NaC5H8NO4, is used extensively as a flavor enhancer. What is its percent composition?

PROBLEM 129QP If 5.00 g of Al is burned completely in excess oxygen gas, 9.45 g of an aluminum oxide is formed. What is the empirical formula of that oxide?