Chemistry Chapter 9 The molar mass rounded to the nearest

Introductory Chemistry: Atoms First, 5e (Russo/Silver)

Chapter 9 Stoichiometry and the Mole

9.1 Multiple-Choice Questions

1) What is the mass in grams of 1.000 mole of P2O5?

A) 239.03 g

B) 61.96 g

C) 142.0 g

D) 46.98 g

2) What is the mass in grams of 1.000 mole of a compound whose formula is C3H7O2?

A) 29.14 g

B) 68.22 g

C) 37.54 g

D) 75.09 g

3) Which of the following has the least number of atoms?

A) (NH4)3PO4

B) Na2P2O3

C) (NH4)2Cr2O7

D) K4Fe(CNO)6

4) Which of the following has the greatest number of atoms?

A) (NH4)3PO4

B) Na2P2O3

C) (NH4)2Cr2O7

D) K4Fe(CNO)6

5) The correct sequence of decreasing number of atoms per formula unit in the following is

________.

A) (NH4)3PO4 > Na2P2O3 > Na3PO4

B) Na3PO4 > (NH4)3PO4 > Na2P2O3

C) Na2P2O3 > Na3PO4 > (NH4)3PO4

D) (NH4)3PO4 > Na3PO4 > Na2P2O3

6) The number of oxygen atoms in 1 mole of Al2(SO4)3 is ________.

A) 3

B) 4

C) 12

D) none of the above

7) The molar mass of Ca3(PO4)2 is ________.

A) 310

B) 279

C) 246

D) 215

8) The molar mass for Pb(CO3)4 is ________.

A) 447

B) 409

C) 327

D) 303

9) Which of the following has a molar mass equal to 133?

A) (NH4)3PO3

B) Ca3(PO4)2

C) Al2(SO3)3

D) Co2(CO3)2

10) Which of the following has the highest molar mass?

A) (NH4)3PO3

B) Ca3(PO4)2

C) Al2(SO3)3

D) Co2(CO3)2

11) Which of the following pairs does not share the same molecular mass when rounded to the

nearest whole number?

A) CH3OH and oxygen gas

B) CO and nitrogen gas

C) C2H6O and C2H4O2

D) C4H10O and C3H6O2

12) The molar mass of a compound XClO3 is 106.5. The molar mass (rounded to the nearest

whole number) of X is ________, which is ________.

A) 39; K

B) 23; Na

C) 7; Li

D) 1; H

13) The molar mass of a compound X(HCO3)2 is 146. The atomic weight of X when rounded to

the nearest whole number is ________, which is ________.

A) 24; Mg

B) 40; Ca

C) 51; V

D) 56; Fe

14) The molecular mass of a compound X(NO3)3 is 213. The atomic mass of X is ________,

which is ________.

A) 27; Al

B) 51; V

C) 56; Fe

D) 59; Co

5

15) The molar mass of a compound Ca(MO3)2 is 160. The atomic mass of M is ________,

which is ________.

A) 12; C

B) 14; N

C) 32; S

D) 35; Cl

16) The molar mass of a compound Al2(XO4)3 is 342. The atomic mass of X is ________,

which is ________.

A) 31; P

B) 32; S

C) 52; Cr

D) 55; Mn

17) Alkanes have the general molecular formula CnH2n+2. Thus, when n = 1, the alkane is CH4,

when n = 2, the alkane is C2H6 etc. If an alkane has a molar mass between 140 and 150, this

alkane is ________.

A) C9H20

B) C12H26

C) C10H22

D) C11H24

18) Alkenes have the general molecular formula CnH2n. Thus, when n = 2, the alkene is C2H4.

If an alkene has a molecular mass between 65 and 75, this alkene is ________.

A) C5H12

B) C5H10

C) C6H3

D) C6H12

19) Alkynes have the general molecular formula CnH2n-2. Thus, when n = 2, the alkyne is

C2H2 etc. If an alkyne has a molecular mass between 75 and 85, this alkyne is ________.

A) C6H10

B) C6H12

C) C5H16

D) C7H12

20) Which of the following quantities does not share the same molar mass as the others when

rounded to the nearest whole number?

A) Al2(SO4)3

B) C12H22O11

C) C24H38O

D) Pb3(PO4)4

21) Which of the following contains the least number of atoms?

A) 1.0 mole C6H14

B) 3.0 moles N2O5

C) 12.0 moles silver

D) 3.0 moles water

22) Which of the following contains the greatest number of atoms?

A) 1.0 mole C6H14

B) 3.0 moles N2O5

C) 12.0 moles silver

D) 3.0 moles water

23) 12 g of carbon is equal to ________.

A) the mass of one atom

B) the mass of one molecule

C) the mass of one mole

D) the mass of half a mole

24) 16 g of oxygen gas is equal to ________.

A) the mass of one atom

B) the mass of one molecule

C) the mass of one mole

D) the mass of half a mole

25) A sample of calcium that contains Avogadro’s number of atoms has a mass of ________.

A) 20 g

B) 40 g

C) 80 g

D) 160 g

26) A sample of calcium that contains one-half Avogadro’s number of atoms has a mass of

________.

A) 20 g

B) 40 g

C) 80 g

D) 160 g

27) A sample of calcium that contains four times Avogadro’s number of atoms has a mass of

________.

A) 20 g

B) 40 g

C) 80 g

D) 160 g

28) A sample of calcium that contains twice Avogadro’s number of atoms has a mass of

________.

A) 20 g

B) 40 g

C) 80 g

D) 160 g

29) A sample of oxygen gas that contains Avogadro’s number of molecules has a mass of

________.

A) 8.0 g

B) 16.0 g

C) 32.0 g

D) 64.0 g

30) A sample of oxygen gas that contains Avogadro’s number of atoms has a mass of ________.

A) 8.0 g

B) 16.0 g

C) 32.0 g

D) 64.0 g

31) A sample of oxygen gas that contains one-half of Avogadro’s number of molecules has a

mass of ________.

A) 8.0 g

B) 16.0 g

C) 32.0 g

D) 64.0 g

32) A sample of oxygen gas that contains twice Avogadro’s number of molecules has a mass of

________.

A) 8.0 g

B) 16.0 g

C) 32.0 g

D) 64.0 g

33) A sample of methane gas that contains Avogadro’s number of molecules has a mass of

________.

A) 8.0 g

B) 16.0 g

C) 32.0 g

D) 64.0 g

34) A sample of methane gas that contains Avogadro’s number of atoms has a mass of ________.

A) 3.2 g

B) 6.4 g

C) 16.0 g

D) 80.0 g

35) Which of the following does not have the same number atoms as the other three choices?

A) three moles Na2SO3

B) six moles of water

C) nine moles NaCl

D) five moles CH4

36) What is the mass of 0.0500 moles aluminum sulfate?

A) 6.15 g

B) 10.95 g

C) 17.1 g

D) 19.8 g

37) What is the molar mass of a compound X if 0.0400 moles weigh 21.6 g?

A) 540

B) 185

C) 216

D) 864

38) 0.3 moles of a certain calcium compound weigh 93 g. This compound may be ________.

A) calcium nitrate

B) calcium chromate

C) calcium phosphate

D) calcium sulfate

39) 0.02 moles of a certain aluminum compound has a mass of 1.56 g. This compound may be

________.

A) aluminum hydroxide

B) aluminum nitrate

C) aluminum cyanide

D) aluminum permanganate

40) 0.05 moles of a certain compound has a mass of 17.1 g. This compound may be ________.

A) aluminum sulfate

B) lead (II) chloride

C) cobalt (III) oxide

D) magnesium carbonate

41) Which of the following will not have the same number atoms as the other three choices?

A) K2Cr2O7

B) (NH4)2S

C) Al(ClO2)3

D) Ba(HCO3)2

42) Which of the following has 14 atoms per formula unit?

A) (NH4)2SO3

B) Al(ClO4)3

C) Pb(CrO4)2

D) Mg3(PO4)2

43) The number of atoms in 2.4 g of magnesium metal is ________.

A) 6.0 × 1022

B) 3.7 × 1022

C) 2.5 × 1022

D) 1.7 × 1022

44) A certain food contains 60 mg of table salt. This is approximately equal to ________ formula

units.

A) 6 × 1023

B) 6 × 1022

C) 6 × 1020

D) 6 × 1026

45) The number of oxygen atoms present in 32.4 g of N2O5 is ________.

A) 5.00

B) 9.03 × 1023

C) 4.51 × 1023

D) 1.81 × 1023

46) Which is the correct statement about one mole of ammonia, NH3?

A) It contains 14 g nitrogen and 3 g hydrogen.

B) It contains 6.02 × 1023 molecules.

C) It contains 1.8 × 1024 atoms of hydrogen.

D) all of the above

47) The number of phosphorus atoms in one molecule of H3PO4 is ________.

A) 1

B) 8

C) 6.02 × 1023

D) 4.8 × 1023

48) The total number of atoms in two moles SO3 is ________.

A) 4

B) 8

C) 1.2 × 1024

D) 4.8 × 1024

49) The mass of one formula unit of Al2(SO4)3 is ________ g.

A) 342

B) 0.0029

C) 5.7 × 10-22

D) 8.0 × 10-27

50) Which of the following does not contain 3.0 × 1024 atoms?

A) 60 g of carbon

B) one mole of methane

C) two moles of water

D) 160 g sulfur

51) Which contains more carbon?

A) 24 g methane

B) 140 g sodium carbonate

C) 40 g carbon monoxide

D) 15 g octane, C8H18

52) One molecule of water contains ________.

A) one mole of hydrogen

B) one mole of oxygen

C) one atom of oxygen

D) 16 g of oxygen

53) The ingredients to make 50 servings of fruit punch are:

∙ 2-1/2 cups white sugar

∙ 6 cups water

∙ 2 (3-ounce) packages strawberry flavored gelatin mix

∙ 1 (46-fluid-ounce) can pineapple juice

∙ 2/3 cup lemon juice

∙ 1 quart orange juice

∙ 2 (2-liter) bottles lemon-lime flavored carbonated beverage

How many servings of punch can you make using the above recipe, if you have 2 gallons of

pineapple juice, 8 (2-liter) bottles of lemon-lime flavored soda and 2 gallons of orange juice?

Assume you have plenty of all the other ingredients.

A) 125 servings

B) 200 servings

C) 278 servings

D) 375 servings

E) 400 servings

54) The mass of CaCl2 that contains 17.8 g of chlorine is ________.

A) 35.6 g

B) 53.4 g

C) 27.9 g

D) 20.5 g

55) The number of moles of chlorine atoms in 12.5 g of carbon tetrachloride is ________.

A) 0.081

B) 0.162

C) 0.325

D) 0.648

56) The mass of oxygen present in 11.7 g of Al2(CO3)3 is ________.

A) 7.20 g

B) 14.4 g

C) 8.10 g

D) 4.05 g

57) Which has more ions—2.0 moles of Al2(SO4)3 or 3.0 moles of Na3PO4?

A) 2.0 moles of Al2(SO4)3

B) 3.0 moles of Na3PO4

C) There are equal number of ions in both ionic compounds.

D) It cannot be determined based on the information given.

58) 0.011 moles of an element has a mass of 2.56 g. This element is ________.

A) Pb

B) V

C) Ac

D) Th

59) What is the mass of hydrogen that will react with 0.203 g of Li to form LiH?

A) 0.015 g

B) 0.030 g

C) 0.060 g

D) 0.120 g

60) What is the mass of sulfur that will react with 0.527 g of copper metal to yield copper (I)

sulfide?

A) 0.066 g

B) 0.132 g

C) 0.264 g

D) 0.198 g

61) 0.842 g chlorine will combine with ________ g of sulfur to produce SCl2.

A) 0.481

B) 1.870

C) 0.305

D) 0.379

62) Two moles of hydrogen react with excess nitrogen to produce ________ moles of ammonia..

N2 + 3 H2 → 2 NH3

A) 1.3

B) 2.0

C) 1.0

D) 6.0

63) If 4 moles of nitrogen produces 2 moles of nitrogen dioxide, then the percent yield is

________.

N2 + 2 O2 → 2 NO2

A) 100%

B) 50%

C) 25%

D) 12.5%

64) If 14 kg of nitrogen yields 23 kg of nitrogen dioxide, then the percent yield for the reaction is

________.

N2 + 2 O2 → 2 NO2

A) 100%

B) 50%

C) 25%

D) 12%

65) The maximum number of moles of water that can be produced from 0.5 moles of C3H8O is

________.

2 C3H8O + 9 O2 → 6 CO2 + 8 H2O

A) 0.5

B) 2

C) 4

D) 8

66) If 5.0 moles of ammonia is produced, then the number of hydrogen molecules consumed is

________.

N2 + 3 H2 → 2 NH3

A) 5.0

B) 7.5

C) 3.2

D) 1.0

67) What is the percent yield for a given process, if 4.0 kg of a product is recovered from a

reaction whose theoretical yield is 5.6 kg?

A) 41%

B) 62%

C) 71%

D) 89%

68) The balanced equation involves the corresponding coefficients ________.

NaHCO3 → Na2CO3 + CO2 + H2O

A) 1: 1: 1: 1

B) 1: 2: 1: 1

C) 2: 1: 1: 1

D) 2: 1: 2: 1

69) The balanced equation involves the corresponding coefficients ________.

H2SO4 + Cu → SO2 + H2O + CuSO4

A) 2: 1: 1: 2: 1

B) 1: 1: 2: 2: 1

C) 2: 1: 2: 1: 1

D) 2: 1: 1: 2: 2

70) The balanced equation involves the corresponding coefficients ________.

NH3 + O2 → NO + H2O

A) 2: 3: 2: 3

B) 2: 5: 2: 3

C) 4: 5: 4: 6

D) 2: 2: 3: 3

71) The balanced equation involves the corresponding coefficients ________.

C2H6O + O2 → CO2 + H2O

A) 1: 2: 2: 3

B) 1: 3: 2: 3

C) 2: 7: 4: 6

D) 2: 9: 4: 6

72) The balanced equation involves the corresponding coefficients ________.

C6H14 + O2 → CO2 + H2O

A) 1: 9: 6: 7

B) 1: 10: 6: 7

C) 2: 19: 12:14

D) 2: 21: 6: 7

73) The balanced equation involves the corresponding coefficients ________.

NaN3 → Na + N2

A) 2: 2: 3

B) 1: 2: 3

C) 2: 1: 3

D) 3: 3: 2