# Stoichiometry. 1. The total number of moles represented by 20 grams of calcium carbonate is (1) 1; (2) 2; (3) 0.1; (4) 0.2.

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1 Stoichiometry 1 The total number of moles represented by 20 grams of calcium carbonate is (1) 1; (2) 2; (3) 01; (4) 02 2 A 44 gram sample of a hydrate was heated until the water of hydration was driven off The anhydrous compound remaining had a mass of 33 grams What is the percentage by mass of water in the hydrate? (1) 25%; (2) 33%; (3) 67%; (4) 75% 3 A sample of neon gas at STP has a mass of 20 grams An equal volume of argon gas at STP will have a mass of (1) 10 g; (2) 20 g; (3) 30 g; (4) 40 g 4 Given the reaction: 2KClO 3 = 2KCl + 3O 2 What is the total number of moles of KCl produced when 150 moles of potassium chlorate is decomposed? (1) 150; (2) 450; (3) 300; (4) What is the freezing point of a solution that contains 100 mole of a nonelectrolyte dissolved in 1000 grams of water? (1) 000 C; (2) 0520 C; (3) -186 C; (4) -372 C 6 If 500 cubic centimeters of 20M HCl is diluted with water to a volume of 1000 cubic centimeters then the molarity of the new solution will be (1) 10M; (2) 20M; (3) 025M; (4) 050M 7 A compound was found by analysis to consist of 856% carbon and 144% hydrogen What is its empirical formula? (1) CH; (2) C ; (3) C 2 H; (4) C 2 8 Given the reaction: N 2 (g) + 3 (g) > 2NH 3 (g) How many liters of ammonia, measured at STP, are produced when 280 grams of nitrogen are completely consumed? (1) 560; (2) 112; (3) 224; (4) The number of moles in 10 grams of calcium is equal to (1) 025; (2) 050; (3) 10; (4) What is the molecular mass of a gas whose density is 125 grams per liter at STP? (1) 140; (2) 179; (3) 200; (4) Given the reaction: Zn + 2HCl > ZnCl2 + H2 How many moles of hydrogen will be formed when 4 moles of HCl are consumed? (1) 6; (2) 2; (3) 8; (4) 4 12 One mole of (NH 4 ) 2 SO 4 has a mass in grams of (1) 50; (2) 54; (3) 64; (4) Which sample of neon contains a total of 1/2 mole of molecules at STP? (1) 112 l; (2) 224 l; (3) 200 g; (4) 400 g 14 A 15 gram sample of a gas has a volume of 30 liters at STP What is the density of the gas? (1) 30 g/l; (2) 20 g/l; (3) 15 g/l; (4) 050 g/l 15 Ca(OH) 2 has a percent by mass of oxygen that is closest to (1) 16; (2) 22; (3) 43; (4) 74 Stoichiometry page 1 of 8

2 16 The empirical formula of a compound is CH Its molecular mass could be (1) 21; (2) 40; (3) 51; (4) Which 10 liter sample has the greatest mass at STP? (3) Cl 2 (g); (4) CH 4 (g) (1) (g); (2) CO 2 (g); 18 Given the reaction: N 2 (g) + O 2 (g) = 2NO(g) What is the total number of liters of NO(g) produced when 20 liters of nitrogen reacts completely with oxygen? (1) 10; (2) 20; (3) 050; (4) What is the molarity of a solution that contains 112 grams of KOH in 200 liters of solution? (1) 100 M; (2) 200 M; (3) 300 M; (4) 400 M 20 A compound consists of 85% silver and 15% fluorine by mass What is its empirical formula? (1) AgF; (2) AgF2; (3) Ag2F; (4) Ag6F 21 One mole of an ideal gas occupies a volume of 224 liters at (1) 273 K and 760 mm; (2) 273 K and 0 mm; (3) 760 degrees C and 273 mm; (4) 0 degrees C and 273 mm 22 If NO 2 is the empirical formula of a compound whose molecular mass is 92, then what is its molecular formula? (1) NO 2 ; (2) N 2 O 4 ; (3) N 3 O 6 ; (4) N 4 O 8 23 Given the reaction: 2 + O > 2 O In the above reaction the total number of grams of oxygen needed to produce 54 grams of water is (1) 36; (2) 48; (3) 61; (4) There is one mole in a sample of (1) 14 g of Li; (2) 14 g of N 2 ; (3) 40 g of He; (4) 40 g of 25 A solution that has 20 grams of calcium bromide in a 050 liter of solution has a molarity of (1) 050; (2) 020; (3) 50; (4) The percent by mass of oxygen in MgO (formula mass = 40) is closest to (1) 16%; (2) 24%; (3) 40%; (4) 60% 27 A compound consists of 146% carbon and 855% chlorine by mass What is the empirical formula? (1) CCl; (2) CCl 2 ; (3) CCl 3 ; (4) CCl 4 28 The gram-molecular mass of a gas is 56 grams Its density at STP in grams per liter is (1) 10; (2) 56; (3) 25; (4) What is the volume of 025 mole of oxygen at STP? (1) 025 liter; (2) 050 liter; (3) 56 liters; (4) 112 liters 30 C is the empirical formula of a compound with a molecular mass of 42 What is the molecular formula of the compound? (1) C H 4 ; (3) C 3 ; (4) C 4 31 The percent by mass of Li in LiNO 3 (formula mass = 69) is closest to (1) 6%; (2) 10%; (3) 18%; (4) 20% 32 Which gas is most dense at STP? (1) CO(g); (2) N 2 (g); (3) NO(g); (4) O 2 (g) 33 A compound contains 050 mole of carbon for each 10 mole of hydrogen The Stoichiometry page 2 of 8

3 empirical formula of this compound is (1) CH; (2) C ; (3) C 2 H; (4) C 2 34 What is the molarity of a solution that contains 28 grams of KOH (formula mass = 56) in 20 liters of solution? (1) 10 M; (2) 20 M; (3) 025 M; (4) 050 M 35 Given the reaction: S + O 2 = SO 2 What is the total number of grams of oxygen needed to react completely with 20 moles of sulfur? (1) 20; (2) 32; (3) 64; (4) A 220 gram sample of a gas occupies 112 liters at STP What is the gram molecular mass of the gas? (1) 112 g; (2) 224 g; (3) 220 g; (4) 440 g 37 A 38 gram sample of F 2 contains about the same number of molecules as (1) 14 g of N 2 ; (2) 20 g of ; (3) 36 g of O; (4) 40 g of Ne 38 Which compound contains the greatest percentage of oxygen by mass? (1) BaO; (2) CaO; (3) MgO; (4) SrO 39 Which gas is less dense than air at STP? (1) CO 2 ; (2) S; (3) NH 3 ; (4) SO 2 40 A compound contains 50% sulfur and 50% oxygen by mass The empirical formula of this compound is (1) SO; (2) SO 2 ; (3) SO 3 ; (4) SO 4 41 What is the total volume (in liters) occupied by 560 grams of nitrogen gas at STP? (1) 112; (2) 224; (3) 336; (4) Given the reaction: N2 + 3H2 = 2NH3 How many grams of ammonia are produced when 10 mole of nitrogen reacts? (1) 85; (2) 17; (3) 34; (4) Which gas has a greater density at STP than air at STP? (1) ; (2) NH 3 ; (3) Cl 2 ; (4) CH 4 44 Eleven grams of a gas occupies 56 liters at STP What is the molecular mass of this gas? (1) 11; (2) 22; (3) 44; (4) A compound which contains 75% carbon and 25% hydrogen by mass has the formula (1) CH 4 ; (3) C 2 ; (4) C 3 46 Three moles of sulfur dioxide at 273 K and 380 mm will have a mass of (1) 64 grams; (2) 96 grams; (3) 192 grams; (4) 384 grams 47 The mass in grams of 200 moles of sulfur dioxide gas is (1) 480; (2) 640; (3) 800; (4) The empirical formula for a compound is CH If the molecular mass of this compound is 78 grams then the molecular formula of the compound is (1) CH; (2) C 2 ; (3) C 5 H 18 ; (4) C 6 49 The percentage of hydrogen in hydrogen sulfide is approximately (1) 1; (2) 2; (3) 6; (4) The density of a gas at STP is 126 grams per liter What is the molecular mass of this gas in grams per mole? (1) 126; (2) 602; (3) 178; (4) 282 Stoichiometry page 3 of 8

4 51 One liter of a solution of nitric acid contains 126 grams of solute The molarity of the solution is (1) 100; (2) 200; (3) 126; (4) What is the mass in grams of 56 liters of neon gas at STP? (1) 5; (2) 10; (3) 15; (4) A 500 ml solution contains 10 grams of NaOH The molarity of this solution is (1) 10 M; (2) 050 M; (3) 025 M; (4) 010 M 54 Nitrogen dioxide has a mass of 460 grams per mole At STP its density would be approximately (1) 103 g/liter; (2) 205 g/liter; (3) 410 g/liter; (4) 230 g/liter 55 Cu(NO 3 ) 2 has a percentage by mass of (3) 256% oxygen; (4) 511% oxygen (1) 850% oxygen; (2) 170% oxygen; 56 Fourteen grams of a gas occupies 112 liters at STP This gas may be (1) carbon dioxide; (2) hydrogen sulfide; (3) hydrogen chloride; (4) nitrogen 57 A compound is found by analysis to consist of 5% hydrogen and 95% flourine What is its empirical formula? (1) HF; (2) F; (3) F 2 ; (4) H 3 F 58 Which gas is least dense at STP? (1) NO; (2) NH 3 ; (3) HCl; (4) S 59 What mass of NaOH (formula mass = 40g) is needed to prepare 500 ml of an 050 M solution? (1) 10 grams; (2) 20 grams; (3) 25 grams; (4) 40 grams 60 A compound contains carbon and hydrogen in the mole ratio 1 to 2 The molecular mass of this compound could be (1) 42; (2) 21; (3) 15; (4) When 200 grams of NaOH is dissolved in 500 ml of solution the concentration of this solution is (1) 10 M; (2) 050 M; (3) 20 M; (4) 40 M 62 Given the reaction: 2 (g) + O 2 (g) = 2 O(g) According to the above equation how many liters of oxygen will combine with 30 liters of hydrogen to produce water? (1) 112; (2) 60; (3) 30; (4) What is the volume of 400 moles of nitrogen gas at STP? (1) 112 l; (2) 224 1; (3) 448 l; (4) 896 l 64 What is the percent by mass of hydrogen in ammonia (formula mass = 170)? (1) 59%; (2) 176%; (3) 214%; (4) 824% 65 Which sample of oxygen gas contains a total of 05 moles at STP? (1) 100 mole; (2) 200 moles; (3) 160 grams; (4) 320 grams 66 Given the reaction: Ca(ClO 3 ) > CaCl 2 + O 2 When the equation is correctly balanced the coefficient in front of the oxygen will be (1) 1; (2) 2; (3) 3; (4) 4 67 If the density of gas X at STP is 100 gram per liter the mass of a mole of this gas is (1) 100 g; (2) 200 g; (3) 112 g; (4) 224 g 68 Given the reaction: N 2 (g) + 3 (g) > 2NH 3 (g) How many liters of hydrogen are required to produce exactly 30 liters of ammonia? (1) 15; (2) 20; (3) 45; (4) 60 Stoichiometry page 4 of 8

5 69 Two moles of nitrogen gas are mixed with 3 moles of hydrogen gas at 273 K and placed in a 224 liter container The pressure of this mixture of gases is (1) 1 atm; (2) 5 atm; (3) 3 atm; (4) 6 atm 70 What is the ratio by mass of hydrogen to oxygen in water? (1) 1-2; (2) 2-1; (3) 1-8; (4) Given the reaction: C 2 H 4 + 3O > 2CO O How many liters of carbon dioxide are produced when 15 liters of oxygen are consumed? (1) 10; (2) 15; (3) 30; (4) The percentage by mass of hydrogen in NH 3 is equal to (1) 1/17 x 100; (2) 3/17 x 100; (3) 17/3 x 100; (4) 6/17 x The empirical formula of a compound is CH 4 The molecular formula of the compound could be (1) CH 4 ; (3) C 3 ; (4) C 4 H What is the total number of molecules contained in 050 mole of O2 at STP? (1) 60 x ; (2) 45 x ; (3) 30 x ; (4) 15 x Which solution contains the greatest number of moles of solute? (1) 05 L of 05 M; (2) 05 L of 2 M; (3) 2 L of 05 M; (4) 2 L of 2 M 76 Given the reaction at STP: N 2 (g) + 3 (g) ----> 2NH 3 (g) What is the total number of liters of NH 3 formed when 20 liters of N 2 reacts completely? (1) 10 L; (2) 20 L; (3) 30 L; (4) 40 L 77 If 100 mole of H2(g) at STP is compared to 100 mole of He(g) at STP, the volumes of the gases would be (1) equal and their masses unequal; (2) equal and their masses equal; (3) unequal and their masses unequal; (4) unequal and their masses equal 78 How many calories of heat are absorbed when 50 grams of water at 100 C are completely vaporized? (Heat of vaporization = 540 cal/g) (1) 590; (2) 5400; (3) 27000; (4) At STP, what mass of CH 4 has the same number of molecules as 64 grams of SO 2? (1) 16 g; (2) 32 g; (3) 64 g; (4) 128 g 80 According to the equation: HCl + NaOH ----> NaCl + H2O The total number of moles of HCl that can be neutralized by 80 grams of NaOH is (1) 10; (2) 20; (3) 36; (4) The density of a gas is 300 grams per liter at STP What is the gram molecular mass of the gas? (1) 747 g; (2) 112 g; (3) 224 g; (4) 672 g 82 A gas has a volume of 1400 milliliters at a temperature of 20 K and a pressure of 760 mm Hg What will be the volume when the temperature is changed to 40 K and the pressure is changed to 380 mm Hg? (1) 350 ml; (2) 750 ml; (3) 1400 ml; (4) 5600 ml 83 Which quantity of helium may be represented by the symbol He? (1) 1 gram; (2) 2 moles; (3) 6 x atoms; (4) 4 liters Stoichiometry page 5 of 8

6 84 When the equation _Na(s) + _ O(l)----> _NaOH(aq) + _ (g) is correctly balanced using smallest whole numbers, the coefficient of the water is (1) 1; (2) 2; (3) 3; (4) 4 85 Given the reaction: 2C 2 (g) + 7O 2 (g)----> 4CO 2 (g) + 6 O(g) At STP, what is the total volume of CO 2 (g) formed when 60 liters (L) of C 2 (g) are completely oxidized? (1) 24 L; (2) 12 L; (3) 60 L; (4) 40 L 86 The percent by mass of carbon in CO 2 is equal to (1) 44/12 x 100; (2) 12/44 x 100; (3) 28/12 x 100; (4) 12/28 x How many grams of KOH are needed to prepare 250 milliliters of a 200 M solution of KOH (formula mass = 560)? (1) 100; (2) 200; (3) 280; (4) What is the gram formula mass of (NH 4 ) 2 SO 4? (1) 160 g; (2) 178 g; (3) 186 g; (4) 132 g 89 What is the maximum number of grams of NH 4 Cl that will dissolve in 200 grams of water at 70 C? (1) 60; (2) 70; (3) 100; (4) Which of the following gases has the greatest density at STP? (1) SO 2 ; (2) CO 2 ; (3) Cl 2 ; (4) N 2 91 At STP, which of the following gases diffuses most rapidly? (1) ; (2) F 2 ; (3) Ne; (4) Xe 92 The total number of molecules in 340 grams of NH 3 is equal to (1) 100 x 224; (2) 200 x 224; (3) 100 x 602 x ; (4) 200 x 602 x What is the empirical formula of a compound whose composition by mass is 50% sulfur and 50% oxygen? (1) SO; (2) SO 2 ; (3) SO 3 ; (4) S 2 O 3 94 What is the total number of kilocalories of heat needed to change 150 grams of ice to water at 0 degrees C? (Heat of fusion = 80 cal/g) (1) 12; (2) 20; (3) 70; (4) When the equation C2H 4 + O > CO 2 + O is balanced using smallest whole numbers, what is the coefficient of the O 2? (1) 1; (2) 2; (3) 3; (4) 4 96 Which quantity is equivalent to 39 grams of LiF? (1) 10 mole; (2) 20 moles; (3) 050 mole; (4) 15 moles 97 If 050 liter of a 12-molar solution is diluted to 10 liter the molarity of the new solution is (1) 24; (2) 60; (3) 12; (4) Given the reaction: 4NH 3 (g) + 5O 2 (g) ---> 4NO(g) + 6 O(g) At constant pressure, how many liters of O 2 (g) would be required to produce 40 liters of NO(g)? (1) 50; (2) 90; (3) 32; (4) A 200-gram sample of helium gas at STP will occupy (1) 112 l; (2) 224 l; (3) 336 l; (4) 448 l 100 What is the molecular formula of a compound whose empirical formula is CH 4 and Stoichiometry page 6 of 8

7 molecular mass is 16? (1) CH 4 H 4 ; (3) C 4 ; (4) C 8 H How many moles of hydrogen atoms are there in one mole of C 6 H 12 O 6 molecules? (1) 1; (2) 6; (3) 24; (4) The density of a gas is 20 grams per liter at STP Its molecular mass is approximately (1) 67; (2) 45; (3) 22; (4) A 5 gram sample of water is heated and the temperature rises from 10 C to 15 C The total amount of heat energy absorbed by the water is (1) 25 cal; (2) 20 cal; (3) 15 cal; (4) 5 cal 104 What is the ratio by mass of carbon to hydrogen in the compound ethane C 2? (1) 6-2; (2) 2-6; (3) 1-4; (4) When the equation NH3 + O2----> HNO3 + H2O is completely balanced using smallest whole numbers, the coefficient of O 2 would be (1) 1; (2) 2; (3) 3; (4) The gram molecular mass of carbon dioxide is the same as the gram molecular mass of (1) CO; (2) SO 2 ; (3) C 2 ; (4) C The molecular mass of a compound is 70 and its empirical formula is C What is the molecular formula of the compound? (1) C 2 H 4 ; (3) C 4 H 10 ; (4) C 5 H Given the reaction: 2Na + 2 O----> 2NaOH + What is the total number of moles of hydrogen produced when 4 moles of sodium react completely? (1) 1; (2) 2; (3) 3; (4) What is the percent by mass of nitrogen in the following compound: Mg(CN) 2? (1) 14/76 x 100; (2) 14/50 x 100; (3) 28/76 x 100; (4) 28/50 x At constant pressure, 50 milliliters (ml) of a gas at 20 C is heated to 30 C The new volume of the gas in milliliters (ml) is equal to (1) 50 x 20/30; (2) 50 x 30/20; (3) 50 x 293/303; (4) 50 x 303/ The heat of vaporization for water is 540 calories per gram What is the minimum number of calories needed to change 400 grams of water at 100 C to steam at the same temperature and pressure? (1) 43,200; (2) 32,600; (3) 540; (4) 21, A compound contains 40% calcium, 12% carbon, and 48% oxygen by mass What is the empirical formula of this compound? (1) CaCO 3 ; (2) CaC 2 O 4 ; (3) CaC 3 O 6 ; (4) CaCO If the density of a gas at STP is 250 grams per liter what is the gram molecular mass of the gas? (1) 250; (2) 224; (3) 560; (4) Which solution will freeze at the lowest temperature? (1) 1 mole of sugar in 500 g of water; (2) 1 mole of sugar in 1000 g of water; (3) 2 moles of sugar in 500 g of water; (4) 2 moles of sugar in 1000 g of water 115 What is the total number of carbon atoms contained in 224 liters of CO gas at STP? (1) 100; (2) 0500; (3) 301 x ; (4) 602 x The volume of an acid required to neutralize exactly 1500 milliliters (ml) of a base Stoichiometry page 7 of 8

8 could be measured most precisely if it were added to the base solution from a (1) 100 ml graduate; (2) 125 ml Erlenmeyer flask; (3) 50 ml buret; (4) 50 ml beaker Stoichiometry page 8 of 8

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