Chemistry (CP) HW Chapter 10 (Due March 28, Test April 1)
Multiple Choice
Identify the choice that best completes the statement or answers the question.
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1. What SI unit is used to measure the number of representative particles in a substance?
a. kilogram
c. kelvin
b. ampere
d. mole
2. How many hydrogen atoms are in 5 molecules of isopropyl alcohol, C H O?
a. 5 (6.02 10 )
c. 35
b. 5
d. 35 (6.02 10 )
3. Which of the following is NOT a representative particle?
a. atom
c. anion
b. cation
d. all of the above
4. Which of the following elements exists as a diatomic molecule?
a. neon
c. nitrogen
b. lithium
d. sulfur
5. All of the following are equal to Avogadro's number EXCEPT ____.
a. the number of atoms of bromine in 1 mol Br
b. the number of atoms of gold in 1 mol Au
c. the number of molecules of nitrogen in 1 mol N
d. the number of molecules of carbon monoxide in 1 mol CO
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6. How many moles of tungsten atoms are in 4.8 10 atoms of tungsten?
a. 8.0 10 moles
c. 1.3 10 moles
b. 8.0 10 moles
d. 1.3 10 moles
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7. How many moles of silver atoms are in 1.8 10
a. 3.0 10
c.
b. 3.3 10
d.
8. How many atoms are in 0.075 mol of titanium?
a. 1.2 10-25
c.
b. 2.2 10
d.
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atoms of silver?
3.0 10
1.1 10
6.4
4.5
10
10
9. How many molecules are in 2.10 mol CO ?
a. 2.53 10 molecules
b. 3.79 10 molecules
c. 3.49 10 molecules
d. 1.26 10 molecules
____ 10. How many atoms are in 3.5 moles of arsenic atoms?
a. 5.8 10 atoms
c. 2.1 10 atoms
b. 7.5 10 atoms
d. 1.7 10 atoms
____ 11. Butanol is composed of carbon, hydrogen, and oxygen. If 1.0 mol of butanol contains 6.0
hydrogen, what is the subscript for the hydrogen atom in C H O?
a. 1
c. 6
b. 10
d. 8
10
atoms of
____ 12. Which of the following is NOT a true about atomic mass?
a. The atomic mass is 12 g for magnesium.
b. The atomic mass is the mass of one mole of atoms.
c. The atomic mass is found by checking the periodic table.
d. The atomic mass is the number of grams of an element that is numerically equal to the
mass in amu.
____ 13. The mass of a mole of NaCl is the ____.
a. molar mass
c. molecular mass
b. atomic mass
d. gram atomic mass
____ 14. What is the molar mass of AuCl3?
a. 96 g
c. 232.5 g
b. 130 g
d. 303.6 g
____ 15. What is the molar mass of (NH ) CO ?
a. 144 g
c. 96 g
b. 138 g
d. 78 g
____ 16. What is the mass in grams of 5.90 mol C H ?
a. 0.0512 g
c. 389 g
b. 19.4 g
d. 673 g
____ 17. What is the number of moles in 432 g Ba(NO ) ?
a. 0.237 mol
c. 1.65 mol
b. 0.605 mol
d. 3.66 mol
____ 18. What is the number of moles of beryllium atoms in 36 g of Be?
a. 0.25 mol
c. 45.0 mol
b. 4.0 mol
d. 320 mol
____ 19. How many moles of CaBr are in 5.0 grams of CaBr ?
a. 2.5 10 mol
c. 4.0 10 mol
b. 4.2 10 mol
d. 1.0 10 mol
____ 20. For which of the following conversions does the value of the conversion factor depend upon the formula of
the substance?
a. volume of gas (STP) to moles
b. density of gas (STP) to molar mass
c. mass of any substance to moles
d. moles of any substance to number of particles
____ 21. What is the mass of silver in 3.4 g AgNO ?
a. 0.025 g
c. 2.2 g
b. 0.64 g
d. 3.0 g
____ 22. What is the mass of oxygen in 250 g of sulfuric acid, H SO ?
a. 0.65 g
c. 16 g
b. 3.9 g
d. 160 g
____ 23. Which combination of temperature and pressure correctly describes standard temperature and pressure, STP?
a. 0 C and 101 kPa
c. 0 C and 22.4 kPa
b. 1 C and 0 kPa
d. 100 C and 100 kPa
____ 24. The molar mass of a gas can be determined from which of the following?
a. the density of the gas at STP
c. Avogadro's number
b. the volume of a mole of the gas
d. none of the above
____ 25. What is the volume, in liters, of 0.500 mol of C H gas at STP?
a. 0.0335 L
c. 16.8 L
b. 11.2 L
d. 22.4 L
____ 26. What is the number of moles in 500 L of He gas at STP?
a. 0.05 mol
c. 22 mol
b. 0.2 mol
d. 90 mol
____ 27. What is the number of moles in 9.63 L of H S gas at STP?
a. 0.104 mol
c. 3.54 mol
b. 0.430 mol
d. 14.7 mol
____ 28. What is the density at STP of the gas sulfur hexafluoride, SF ?
a. 0.153 g/L
c. 3270 g/L
b. 6.52 g/L
d. 3.93 10 g/L
____ 29. The molar mass of a certain gas is 49 g. What is the density of the gas in g/L at STP?
a. 3.6 10 g/L
c. 2.2 g/L
b. 0.46 g/L
d. 71 g/L
____ 30. A 22.4-L sample of which of the following substances, at STP, would contain 6.02 10 representative
particles?
a. oxygen
c. cesium iodide
b. gold
d. sulfur
____ 31. If the density of an unknown gas Z is 4.50 g/L at STP, what is the molar mass of gas Z?
a. 0.201 g/mol
c. 26.9 g/mol
b. 5.00 g/mol
d. 101 g/mol
____ 32. Which of the following gas samples would have the largest number of representative particles at STP?
a. 12.0 L He
c. 0.10 L Xe
b. 7.0 L O
d. 0.007 L SO
____ 33. Given 1.00 mole of each of the following gases at STP, which gas would have the greatest volume?
a. He
c. SO
b. O
d. All would have the same volume.
____ 34. To determine the formula of a new substance, one of the first steps is to find the ____.
a. molar mass
c. volume at STP
b. percent composition
d. number of particles per mole
____ 35. What information is needed to calculate the percent composition of a compound?
a. the weight of the sample to be analyzed and its density
b. the weight of the sample to be analyzed and its molar volume
c. the formula of the compound and the atomic mass of its elements
d. the formula of the compound and its density
____ 36. If 60.2 grams of Hg combines completely with 24.0 grams of Br to form a compound, what is the percent
composition of Hg in the compound?
a. 28.5%
c. 71.5%
b. 39.9%
d. 60.1%
____ 37. What is the percent composition of chromium in BaCrO ?
a. 4.87%
c. 20.5%
b. 9.47%
d. 25.2%
____ 38. If 20.0 grams of Ca combines completely with 16.0 grams of S to form a compound, what is the percent
composition of Ca in the compound?
a. 1.25%
c. 44.4%
b. 20.0%
d. 55.6%
____ 39. What is the percent composition of carbon, in heptane, C H ?
a. 12%
c. 68%
b. 19%
d. 84%
____ 40. What is the percent by mass of carbon in acetone, C H O?
a. 20.7%
c. 1.61%
b. 62.1%
d. 30.0%
____ 41. Which expression represents the percent by mass of nitrogen in NH4NO3?
a. 14 g N/80 g NH NO
c. 80 g NH NO /14 g N 100%
100%
b. 28 g N/80 g NH NO
d. 80 g NH NO /28 g N 100%
100%
____ 42. Which of the following compounds has the lowest percent gold content by weight?
a. AuOH
c. AuCl
b. Au(OH)
d. AuI
____ 43. Which of the following compounds has the highest oxygen content, by weight?
a. Na O
c. BaO
b. CO
d. H O
____ 44. Which of the following is NOT an empirical formula?
a. C N H
c. BeCr O
b. C H O
d. Sb S
____ 45. Which of the following compounds have the same empirical formula?
a. CO and SO
c. C H and C H
b. C H and C H
d. C H and C H
____ 46. What is the empirical formula of a compound that is 40% sulfur and 60% oxygen by weight?
a. SO
c. SO
b. SO
d. S O
____ 47. What is the empirical formula of a substance that is 53.5% C, 15.5% H, and 31.1% N by weight?
a. C HN
c. C H N
b. C H N
d. CH N
____ 48. The ratio of carbon atoms to hydrogen atoms to oxygen atoms in a molecule of dicyclohexyl maleate is 4 to 6
to 1. What is its molecular formula if its molar mass is 280 g?
a. C H O
c. C H O
b. C H O
d. C H O
____ 49. Which of the following is NOT true about empirical and molecular formulas?
a. The molecular formula of a compound can be the same as its empirical formula.
b. The molecular formula of a compound can be some whole-number multiple of its
empirical formula.
c. Several compounds can have the same empirical formula, but have different molecular
formulas.
d. The empirical formula of a compound can be triple its molecular formula.
____ 50. Which of the following sets of empirical formula, molar mass, and molecular formula is correct?
a. CH, 78 g, C H
c. CaO, 56 g, Ca O
b. CH N, 90 g, C H N
d. C H O, 120 g, C H O