Y (3) XY 2 (2) X 2 Y (4) XY 3

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1 1. Which represents both an empirical and a molecular formula (1) P 2 5 (3) C 3 (2) N 2 4 (4) C 6 H What is the empirical formula of a compound with the molecular formula C 6 H 12 6 (1) C 4 4 (3) C 2 2 (2) C 3 3 (4) CH 2 3. What is the empirical formula of a compound that contains 0.20 mole of nitrogen atoms and 0.40 mole of oxygen atoms (1) N 2 (3) N 2 4 (2) N 2 (4) N Which compound has the same empirical and molecular formula (1) C 2 (3) C (2) C 3 (4) H An example of an empirical formula is (1) C 2 H 2 (3) C 2 Cl 2 (2) H 2 2 (4) CaCl 2 6. Which compound has the empirical formula CH 2 (1) CH 3 H (3) HCH (2) CH 3 CH 2 H (4) CH 3 CH 7. Which compound has the empirical formula CH (1) C (3) C 6 (4) C 3 8. What is the total number of atoms represented in the formula CuS 4 5H 2 (1) 8 (3) 21 (2) 13 (4) What is the total number of hydrogen atoms required to form 1 molecule of C 3 H 5 (H) 3 (1) 1 (3) 3 (2) 5 (4) The molecular formula of a compound is represented by X 3 Y 6. What is the empirical formula of this compound (1) X 3 Y (3) XY 2 (2) X 2 Y (4) XY The empirical formula of a compound is CH 2. The molecular formula of this compound could be (1) C (3) C 2 H 2 (4) C A compound has the empirical formula N 2. Its molecular formula could be (1) N 2 (3) N 4 2 (2) N 2 (4) N A compound contains nitrogen and oxygen in the mole ratio of 1:1. The molecular mass of this compound could be (1) 14 (3) 30 (2) 16 (4) Which formulas could represent the empirical formula and the molecular formula of a given compound (1) CH 2, C 4 4 (3) C, C 5 H 12 (2) CH, C 6 H 12 6 (4) CH 2, C A compound has a molecular mass of 54 and an empirical formula of C 2 H 3. What is the molecular formula of the compound (1) C 2 H 3 (3) C 5 (2) C 4 (4) C 6 H What is the total number of moles of atoms represented by the formula Al(C 2 H 3 2 ) 3 (1) 22 (3) 8 (2) 11 (4) 4

2 17. A compound whose empirical formula is N 2 could have a molecular mass of (1) 23 (3) 92 (2) 39 (4) The formula H 2 2 is an example of (1) a molecular formula (2) an empirical formula (3) an ionic formula (4) an organic formula 19. What is the molecular formula of a compound that has a molecular mass of 54 and the empirical formula C 2 H 3 (1) C 2 H 3 (3) C 6 H 9 (2) C 4 (4) C 8 H A compound has the empirical formula CH 2 and a gram-formula mass of 60. grams per mole. What is the molecular formula of this compound (1) CH 2 (3) C 3 2 (4) C Which formula is both a molecular and an empirical formula (1) C 6 H 12 6 (3) C 3 2 (4) C What is the gram formula mass of Na 2 C 3 10H 2 (1) 106 g (3) 266 g (2) 142 g (4) 286 g 23. What is the gram formula mass of (NH 4 ) 2 S 4 (1) 66.0 g (3) 114 g (2) 94.0 g (4) 132 g 24. What is the gram formula mass of Mg(Cl 3 ) 2 (1) 107 g (3) 174 g (2) 142 g (4) 191 g 25. What is the gram formula mass of CuS 4 5H 2 (1) 160. g (3) 186 g (2) 178 g (4) 250. g 26. Which substance has the greatest molecular mass (1) H 2 2 (3) CF 4 (2) N (4) I What is the gram formula mass of Ca 3 (P 4 ) 2 (1) 196 g (3) 245 g (2) 214 g (4) 310. g 28. The molar mass of Ba(H) 2 is (1) g (3) g (2) g (4) g 29. A 1.0-mole sample of krypton gas has a mass of (1) 19 g (3) 39 g (2) 36 g (4) 84 g 30. The gram-formula mass of N 2 is defined as the mass of (1) one mole of N 2 (2) one molecule of N 2 (3) two moles of N (4) two molecules of N 31. How many moles of water are contained in mole of CuS 4 5H 2 (1) 1.25 (3) 40.0 (2) 4.50 (4) Which quantity can correctly be represented by the symbol "He" (1) 1 mole of atoms (3) atoms (2) 10 grams of atoms (4) 11.2 liters of atoms 33. What is the total number of moles of atoms in one mole of (N ) 2 S 4 (1) 10 (3) 14 (2) 11 (4) 15

3 34. What is the total number of moles of atoms present in 1 mole of Ca 3 (P 4 ) 2 (1) 13 (3) 8 (2) 10 (4) In a sample of oxygen gas at STP, which represents the greatest number of molecules (1) one mole (3) one molecule (2) one gram (4) one liter 36. Which represents the greatest mass of chlorine (1) 1 mole of chlorine (2) 1 atom of chlorine (3) 1 gram of chlorine (4) 1 molecule of chlorine 37. What is the total number of moles of atoms present in 1 gram formula mass of Pb(C 2 H 3 2 ) 2 (1) 9 (3) 3 (2) 14 (4) The gram-formula mass of a compound is 48 grams. The mass of 1.0 mole of this compound is (1) 1.0 g (3) 48 g (2) 4.8 g (4) 480 g 39. The gram molecular mass of C 2 is the same as the gram molecular mass of (1) C (3) C 2 (2) S 2 (4) C Which sample contains the same number of atoms as 24 grams of carbon (1) 80. g Ar (3) 10. g Ne (2) 24 g Mg (4) 4.0 g He 42. Which sample contains the same number of atoms as a gram of He (1) 6 g of C (3) 4 g of (2) 7 g of Li (4) 9 g of F 43. What is the gram-molecular mass of a compound if 5 moles of the compound has a mass of 100 grams (1) 5 g (3) 100 g (2) 20 g (4) 500 g 44. What is the total mass in grams of 0.75 mole of S 2 (1) 16 g (3) 32 g (2) 24 g (4) 48 g 45. What is the total mass of oxygen in 1.00 mole of Al 2 (Cr 4 ) 3 (1) 192 g (3) 64.0 g (2) 112 g (4) 48.0 g 46. The total number of moles represented by 20 grams of CaC 3 is (1) 1 (3) 0.1 (2) 2 (4) ne mole of 2 has approximately the same mass as one mole of (1) C (3) LiH (2) S (4) Cl The number of moles of molecules in a gram sample of Cl 2 is (1) (3) 41. Which quantity is equivalent to 39 grams of LiF (1) 1.0 mole (3) 0.50 mole (2) 2.0 moles (4) 1.5 moles (2) (4) 49. Which sample contains a mole of atoms (1) 23 g Na (3) 42 g Kr (2) 24 g C (4) 78 g K

4 50. A sample of a compound contains 65.4 grams of zinc, 12.0 grams of carbon, and 48.0 grams of oxygen. What is the mole ratio of zinc to carbon to oxygen in this compound (1) 1:1:2 (3) 1:4:6 (2) 1:1:3 (4) 5:1:4 51. What is the molecular formula of a compound with an empirical formula of CH and a molecular mass of 78 (1) C 6 (3) C 2 H 2 (2) C 4 H 10 (4) CH 52. What is the molecular formula of a compound with the empirical formula P 2 5 and a grammolecular mass of 284 grams (1) P 2 5 (3) P 10 4 (2) P 5 2 (4) P 4 l0 53. Vitamin C has an empirical formula of C 3 3 and a molecular mass of 176. What is the molecular formula of vitamin C (1) C 3 3 (3) C 9 H 12 9 (2) C 6 6 (4) C What is the molecular formula of a compound that has a molecular mass of 42 and an empirical formula of CH 2 (1) CH 2 (3) C 3 (4) C 4 H l2 55. What is the molecular formula of a compound that has a molecular mass of 92 and an empirical formula of N 2 (1) N 2 (3) N 3 6 (2) N 2 4 (4) N If the empirical formula for an organic compound is CH 2, then the molecular mass of the compound could be (1) 135 (3) 45 (2) 60 (4) A compound has a gram formula mass of 56 grams per mole. What is the molecular formula for this compound (1) CH 2 (3) C 3 (4) C If the density of a gas at STP is 2.50 grams per liter, what is the gram molecular mass of the gas (1) 2.50 (3) 56.0 (2) 22.4 (4) Which gas has a density of 1.52 grams per liter at STP (1) H 2 S (3) N (2) C (4) C 60. At STP, what is the density of a gas that has a gram molecular mass of 32 grams (1) 0.70 g/l (3) 3.2 g/l (2) 2.0 g/l (4) 1.4 g/l 61. If the density of gas X at STP is 1.00 gram per liter, the mass of a mole of this gas is (1) 1.00 g (3) 11.2 g (2) 2.00 g (4) 22.4 g 62. A sample of an unknown gas at STP has a density of gram per liter. What is the gram molecular mass of this gas (1) 2.81 g (3) 22.4 g (2) 14.1 g (4) 63.0 g 63. What is the mass of 1.00 mole of a gas if 28.0 grams of this gas occupies 22.4 liters at STP (1) 1.00 g (3) 22.4 g (2) 1.25 g (4) 28.0 g 64. What is the molecular mass of a gas whose density is 1.4 grams per liter at STP (1) 16 (3) 31 (2) 22 (4) At STP, 25.0 liters of a gas has a mass of 50.0 grams. What is the gram molecular mass of the gas (1) 75.0 g (3) 25.0 g (2) 44.8 g (4) 11.2 g

5 66. If 28.0 grams of a gas occupies 22.4 liters at STP, the gas could be (1) C (3) C 2 H 2 (4) C Air consists of approximately 79% nitrogen and 19% oxygen. Which gas is less dense than air at STP (1) C 2 (3) NH 3 (2) H 2 S (4) S Eleven grams of a gas occupies 5.6 liters at STP. What is the molecular mass of this gas (1) 11 (3) 44 (2) 22 (4) Air consists of approximately 79% nitrogen and 19% oxygen. Which gas is more dense than air at STP (1) ammonia (3) carbon monoxide (2) methane (4) carbon dioxide 70. An 80 gram sample of a gas has a volume of 44.8 liters at STP. Its molecular mass is (1) 80 (3) 30 (2) 20 (4) A compound contains 53% Al and 47% by mass. What is the empirical formula of this compound (1) Al (3) Al 2 3 (2) Al 2 (4) Al A compound consists of 40.% sulfur and 60.% oxygen by mass. What is the empirical formula of this compound (1) S (3) S 3 (2) S 2 (4) S A compound contains 57% sulfur and 43% oxygen by mass. What is the empirical formula of this compound (1) S (3) S 3 (2) S 2 (4) S A compound contains 40% calcium, 12% carbon, and 48% oxygen by mass. What is the empirical formula of this compound (1) CaC 3 (3) CaC 3 6 (2) CaC 2 4 (4) CaC What is the empirical formula of a compound if a sample contains 8.52 grams of carbon and 1.42 grams of hydrogen (1) C 2 H (3) CH (2) CH 2 (4) C 2 H A compound contains 16% carbon and 84% sulfur by mass. What is the empirical formula of this compound (1) CS 2 (3) CS S 2 (4) C 2 S 77. A 16.0-gram sample of a compound containing only copper and sulfur is decomposed to produce 12.8 grams of copper and 3.2 grams of sulfur. The empirical formula of the compound is (1) CuS (3) CuS 2 (2) Cu 2 S (4) Cu 2 S A compound consists of 14.6% carbon and 85.4% chlorine by mass. What is the empirical formula (1) CCl (3) CCl 3 (2) CCl 2 (4) CCl What is the empirical formula of a compound that contains 85% Ag and 15% F by mass (1) AgF (3) AgF 2 (2) Ag 2 F (4) Ag 2 F In which compound is the percent composition by mass of chlorine equal to 42% (1) HCl (gram-formula mass = 52 g/mol) (2) HCl 2 (gram-formula mass = 68 g/mol) (3) HC1 3 (gram-formula mass = 84 g/mol) (4) HCl 4 (gram-formula mass = 100. g/mol)

6 Base your answers to questions 81 and 82 on the table below shows the data collected during the heating of a 5.0 gram sample of a hydrated salt. 81. After 60. minutes, how many grams of water appear to remain in the salt (1) 0.00 (3) 1.9 (2) 2.0 (4) What is the percent of water in the original sample (1) 82.% (3) 30.% (2) 60.% (4) 40.% 83. The percent by mass of oxygen in H 2 C 2 4 is equal to 85. The percentage by mass of hydrogen in H 3 P 4 is equal to (1) (2) (3) (4) What is the ratio by mass of hydrogen to oxygen in H 2 (1) 1:2 (3) 1:8 (2) 2:1 (4) 8:1 87. A student determining the percent by mass of water in a hydrated sample of salt obtained the following data: Mass of hydrate 6.25 g Mass of sample after 1st heating 5.12 g Mass of sample after 2nd heating 5.12 g The correct expression for obtaining the percent by mass of water in the sample is (1) (3) (1) (3) (2) (4) (2) (4) 84. An 8.24-gram sample of a hydrated salt is heated until it has a constant mass of 6.20 grams. What was the percent by mass of water contained in the original sample (1) 14.1% (3) 32.9% (2) 24.8% (4) 75.2% 88. A 60. gram sample of LiCl H 2 is heated in an open crucible until all of the water has been driven off. What is the total mass of LiCl remaining in the crucible (1) 18 g (3) 42 g (2) 24 g (4) 60 g 89. A 10.0 gram sample of a hydrate was heated until all the water of hydration was driven off. The mass of anhydrous product remaining was 8.00 grams. What is the percent of water in the hydrate (1) 12.5% (3) 25.0% (2) 20.0% (4) 80.0%

7 90. A student obtained the following data to determine the percent by mass of water in a hydrate. What is the approximate percent by mass of the water in the hydrated salt (1) 2.5% (3) 88% (2) 12% (4) 98% S 3 (g) 2 S 2 (g) + 2 (g) What type of reaction is shown above (1) synthesis (3) single replacement (2) decomposition (4) double replacement 92. H 2 (g) + I 2 (g) 2 HI(g) What type of reaction is shown above (1) synthesis (3) single replacement (2) decomposition (4) double replacement 93. Mg(s) + 2 HCl(aq) MgCl 2 (aq) + H 2 (g) What type of reaction is shown above (1) synthesis (3) single replacement (2) decomposition (4) double replacement 94. Which two solutions, when mixed together, will undergo a double replacement reaction and form a white, solid substance (1) NaCl(aq) and LiN 3 (aq) (2) KCl(aq) and AgN 3 (aq) (3) KCl(aq) and LiCl(aq) (4) NaN 3 (aq) and AgN 3 (aq) 95. Which equation represents a double replacement reaction (1) 2 Na + 2 H 2 2 NaH + H 2 (2) CaC 3 Ca + C 2 (3) LiH + HCl LiCl + H 2 (4) C C H Which balanced equation represents a chemical change (1) H 2 ( ) + energy H 2 (g) (2) 2H 2 ( ) + energy 2H 2 (g) + 2 (g) (3) H 2 ( ) H 2 (s) + energy (4) H 2 (g) H 2 ( ) + energy 97. What is conserved during a chemical reaction (1) energy, only (2) matter, only (3) both matter and energy (4) neither matter nor energy 98. When the equation NH N 2 + H 2 is completely balanced using the smallest whole numbers, the coefficient of the 2 will be (1) 1 (3) 3 (2) 2 (4) Given the reaction: 2 Na + 2 H 2 2 NaH + H 2 What is the total number of moles of hydrogen produced when 4 moles of sodium react completely (1) 1 (3) 3 (2) 2 (4) 4

8 100. Given the reaction: 2 NaH + H 2 S 4 Na 2 S H 2 What is the total number of moles of NaH needed to react completely with 2 moles of H 2 S 4 (1) 1 (3) 0.5 (2) 2 (4) Given the reaction: Ca + 2 H 2 Ca(H) 2 + H 2 How many moles of H 2 are needed to react completely with 2.0 moles of Ca (1) 1.0 mole (3) 0.50 mole (2) 2.0 moles (4) 4.0 moles 102. In the reaction Fe C 2 Fe + 3 C 2, what is the total number of moles of C used to produce 112 grams of iron (1) 1.0 (3) 3.0 (2) 2.0 (4) Given the reaction: Mg + 2 HCl MgCl 2 + H 2 What is the total number of grams of Mg consumed when 0.50 mole of H 2 is produced (1) 6.0 g (3) 3.0 g (2) 12 g (4) 24 g 104. Given the reaction: 4 Al Al 2 3 How many moles of Al 2 3 will be formed when 27 grams of Al reacts completely with 2 (1) 1.0 (3) 0.50 (2) 2.0 (4) Given the reaction: Cu + 4 HN 3 Cu(N 3 ) H N 2 What is the total mass of H 2 produced when 32 grams of Cu is completely consumed (1) 9.0 g (3) 36 g (2) 18 g (4) 72 g 106. Given the balanced equation: NaH + HCl NaCl + H 2 What is the total number of grams of H 2 produced when 116 grams of the product, NaCl, is formed (1) 9.0 g (3) 36 g (2) 18 g (4) 54 g 107. Given the reaction: 2 H H 2 The total number of grams of 2 needed to produce 54 grams of water is (1) 36 (3) 61 (2) 48 (4) Given the balanced equation representing a reaction: 2H H 2 What is the total mass of water formed when 8 grams of hydrogen reacts completely with 64 grams of oxygen (1) 18 g (3) 56 g (2) 36 g (4) 72 g 109. Given the reaction: 2 C C H 2 What is the total number of C 2 molecules produced when one mole of C 2 is consumed (1) (3) 3( ) (2) 2( ) (4) 4( )

9 110. Given the reaction: Mg + H 2 S 4 MgS 4 + H 2 How many grams of H 2 S 4 are needed to produce exactly 11.2 liters of H 2, measured at STP (1) 24.5 (3) 98.0 (2) 49.0 (4) Given the reaction N 2 (g) + 3 H 2 (g) 2 NH 3 (g) How many liters of ammonia, measured at STP, are produced when 28.0 grams of nitrogen is completely consumed (1) 5.60 (3) 22.4 (2) 11.2 (4) Given the reaction: 2 S 2 (g) + 2 (g) 2 S 3 (g) What is the total number of liters of 2 (g), measured at STP, that will react completely with 4.00 moles of S 2 (1) 1.00 L (3) 22.4 L (2) L (4) 44.8 L 113. What is the mass of atoms of neon (1) 1.0 g (3) 10. g (2) 0.50 g (4) 20. g 114. What is the total number of atoms contained in 2.00 moles of nickel (1) 58.9 (3) (2) 118 (4)

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