Chapter 3 3 What is the mass % of carbon in dimethyl sulfoxide

3.3 Algorithmic Questions

1) When the following equation is balanced, the coefficients are ________.

C8H18 + O2 → CO2 + H2O

A) 4, 50, 16, 18

B) 1, 5, 2, 2

C) 2, 2, 7, 1

D) 1, 13, 8, 9

E) 2, 25, 16, 18

2) The formula weight of PbCO3 is ________ amu.

A) 279.2

B) 112.0

C) 118.0

D) 267.2

E) 235.2

3) The formula weight of Zn(ClO4)2 is ________ amu.

A) 164.7

B) 128.0

C) 79.0

D) 264.1

E) 116.7

4) The formula weight of LiClO4 is ________ amu.

A) 212.3

B) 101.0

C) 52.0

D) 106.3

E) 58.3

5) The molecular weight of 2-propanol (C3H7OH), known as rubbing alcohol, is ________ amu (rounded

to one decimal place).

A) 59.1

B) 29.0

C) 60.1

D) 12.0

E) 34.0

6) The molecular weight of ethanol (C2H5OH), rounded to one decimal place, is ________ amu.

A) 45.1

B) 26.0

C) 25.0

D) 46.1

E) 29.0

7) The molecular weight of maltose (C12H22O11), rounded to one decimal place, is ________ amu.

A) 507.2

B) 182.0

C) 15.0

D) 342.3

E) 29.0

8) Determine the mass percent (to the hundredths place) of C in sodium bicarbonate (NaHCO3).

9) What is the mass % of carbon in dimethylsulfoxide (C2H6SO) rounded to three significant figures?

A) 25.4

B) 28.6

C) 30.7

D) 7.74

E) 78.1

10) What is the mass % of carbon in dimethylsulfoxide (C2H6SO) rounded to three significant figures?

A) 25.4

B) 28.6

C) 30.7

D) 7.74

E) 78.1

11) What is the mass % of aluminum in aluminum sulfide (Al2(SO4)3) rounded to three significant

figures?

A) 7.90

B) 23.7

C) 15.8

D) 31.6

E) 342.2

12) What is the mass % of oxygen in lead (II) nitrate (Pb(NO3)2) rounded to three significant figures?

A) 4.83

B) 19.3

C) 29.0

D) 14.5

E) 0.331

13) There are ________ mol of carbon atoms in 5 mol of dimethylsulfoxide (C2H6SO).

A) 4

B) 8

C) 10

D) 12

E) 14

14) 1 mole of which of the following will contain the largest number of atoms?

A) sodium

B) magnesium

C) mercury

D) neon

E) 1 mole of any element will contain the same number of atoms.

15) 1 mole of which of the following will have the largest mass?

A) rubidium

B) magnesium

C) gold

D) neon

E) 1 mole of any element will contain the same mass.

16) How many grams of hydrogen are in 46 g of CH4O?

A) 5.8

B) 1.5

C) 2.8

D) 0.36

E) 180

17) There are ________ atoms of oxygen in 300 molecules of CH3CO2H.

A) 300

B) 600

C) 150

D) 3.6 × 1026

E) 1.0 × 10–22

18) How many grams of oxygen are in 56 g of C2H2O2?

A) 11

B) 19

C) 26

D) 31

E) 49

19) A 30.5 gram sample of glucose (C6H12O6) contains ________ atoms of carbon.

A) 9.17 × 1024

B) 6.12 × 1023

C) 1.70 × 1022

D) 1.69 × 10–24

E) 1.02

20) A 1.36-g sample of magnesium nitrate, Mg(NO3)2, contains ________ mol of this compound.

A) 2.32

B) 1.65

C) 0.111

D) 0.0182

E) 0.00917

21) A 22.5-g sample of ammonium carbonate contains ________ mol of ammonium ions.

A) 0.467

B) 0.288

C) 0.234

D) 2.14

E) 3.47

22) What is the mass in grams of 9.76 × 1012 atoms of naturally occurring potassium?

A) 2.41 × 1012

B) 2.50 × 1011

C) 6.34 × 10–10

D) 1.62 × 10–11

E) 3.82 × 1014

23) What is the mass in grams of 2.00 × 105 atoms of naturally occurring neon?

A) 6.07 × 1019

B) 9910

C) 797

D) 3.32 × 10–19

E) 4040000

24) How many moles of pyridine (C5H5N) are contained in 4.14 g of pyridine?

A) 0.0523

B) 327

C) 6.88 × 10–24

D) 2.49 ×1024

E) 79.1

25) How many moles of lithium phosphate (Li3PO4) are contained in 66.6 g of lithium phosphate?

A) 0.575

B) 7710

C) 1.11 × 10–22

D) 4.01 × 1025

E) 116

26) How many grams of calcium cyanide (Ca(CN)2) are contained in 0.69 mol of calcium cyanide?

A) 61

B) 0.0078

C) 1.2 × 10–24

D) 4.2 × 1023

E) 88

27) How many grams of phenol (C6H5OH) are contained in 5.50 mol of phenol?

A) 518

B) 0.0584

C) 9.14 × 10–24

D) 3.31 × 1024

E) 94.1

28) What is the empirical formula of a compound that is 66.6% C, 11.2% H, and 22.2% O by mass?

A) C4HO

B) C6HO2

C) C8H16O2

D) C6H11O

E) C4H8O

29) A certain alcohol contains only three elements, carbon, hydrogen, and oxygen. Combustion of a 60.00

gram sample of the alcohol produced 114.6 grams of CO2 and 70.44 grams of H2O. What is the empirical

formula of the alcohol?

30) Lithium and nitrogen react to produce lithium nitride:

6Li (s) + N2 (g) → 2Li3N (s)

How many moles of N2 are needed to react with 0.550 mol of lithium?

A) 3.30

B) 0.550

C) 0.183

D) 1.65

E) 0.0917

31) The combustion of propane (C3H8) produces CO2 and H2O:

C3H8 (g) + 5O2 (g) → 3CO2 (g) + 4H2O (g)

The reaction of 2.5 mol of O2 will produce ________ mol of H2O.

A) 4.0

B) 3.0

C) 2.5

D) 2.0

E) 1.0

32) Magnesium and nitrogen react in a combination reaction to produce magnesium nitride:

3 Mg + N2 → Mg3N2

In a particular experiment, a 8.33-g sample of N2 reacts completely. The mass of Mg consumed is

________ g.

A) 7.23

B) 21.7

C) 28.9

D) 0.92

E) 13.9

33) The combustion of ammonia in the presence of excess oxygen yields NO2 and H2O:

4 NH3 (g) + 7O2 (g) → 4 NO2 (g) + 6 H2O (g)

The combustion of 14.4 g of ammonia consumes ________ g of oxygen.

A) 13.5

B) 28.8

C) 54.1

D) 47.3

E) 94.6

34) Lithium and nitrogen react to produce lithium nitride:

6Li (s) + N2 (g) → 2Li3N (s)

How many moles of lithium nitride are produced when 0.330 mol of lithium react in this fashion?

A) 0.110

B) 0.660

C) 0.0550

D) 0.990

E) 0.165

35) Lithium and nitrogen react in a combination reaction to produce lithium nitride:

6Li (s) + N2 (g) → 2Li3N (s)

How many moles of lithium are needed to produce 0.45 mol of Li3N when the reaction is carried out in

the presence of excess nitrogen?

A) 0.23

B) 1.4

C) 0.15

D) 0.30

E) 2.7

36) Automotive air bags inflate when sodium azide decomposes explosively to its constituent elements:

2NaN3 (s) → 2Na (s) + 3N2 (g)

How many moles of N2 are produced by the decomposition of 1.75 mol of sodium azide?

A) 1.17

B) 5.25

C) 2.63

D) 0.583

E) 0.875

37) Automotive air bags inflate when sodium azide decomposes explosively to its constituent elements:

2NaN3 (s) → 2Na (s) + 3N2 (g)

How many grams of sodium azide are required to produce 28.0 g of nitrogen?

A) 1.50

B) 0.666

C) 65.0

D) 43.3

E) 97.5

38) Magnesium burns in air with a dazzling brilliance to produce magnesium oxide:

2Mg (s) + O2 (g) → 2MgO (s)

How many moles of O2 are consumed when 3.55 mol of magnesium burns?

A) 0.146

B) 0.563

C) 3.55

D) 7.10

E) 1.78

39) Calcium carbide (CaC2) reacts with water to produce acetylene (C2H2):

CaC2 (s) + 2H2O (g) → Ca(OH)2 (s) + C2H2 (g)

Production of 6.5 g of C2H2 requires consumption of ________ g of H2O.

A) 2.3

B) 4.5

C) 9.0

D) 480

E) 0.048

40) Lead (II) carbonate decomposes to give lead (II) oxide and carbon dioxide:

PbCO3 (s) → PbO (s) + CO2 (g)

________ grams of lead (II) oxide will be produced by the decomposition of 8.75 g of lead (II) carbonate?

A) 0.41

B) 2.50

C) 0.00936

D) 7.31

E) 11.7

41) Lithium and nitrogen react in a combination reaction to produce lithium nitride:

6Li (s) + N2 (g) → 2Li3N (s)

In a particular experiment, 2.50-g samples of each reagent are reacted. The theoretical yield of lithium

nitride is ________ g.

A) 2.51

B) 2.09

C) 12.5

D) 4.18

E) 6.2

42) Magnesium burns in air with a dazzling brilliance to produce magnesium oxide:

2Mg (s) + O2 (g) → 2MgO (s)

When 5.50 g of magnesium burns, the theoretical yield of magnesium oxide is ________ g.

A) 5.50

B) 9.12

C) 0.226

D) 4.56

E) 18.2

43) Calcium oxide reacts with water in a combination reaction to produce calcium hydroxide:

CaO (s) + H2O (l) → Ca(OH)2 (s)

A 3.50-g sample of CaO is reacted with 3.38 g of H2O. How many grams of water remain after

completion of reaction?

A) 0.00

B) 0.00694

C) 2.25

D) 1.04

E) 0.125

44) If 588 grams of FeS2 is allowed to react with 352 grams of O2 according to the following equation,

how many grams of Fe2O3 are produced?

FeS2 + O2 → Fe2O3 + SO2

45) Calcium oxide reacts with water in a combination reaction to produce calcium hydroxide:

CaO (s) + H2O (l) → Ca(OH)2 (s)

In a particular experiment, a 2.00-g sample of CaO is reacted with excess water and 2.14 g of Ca(OH)2 is

recovered. What is the percent yield in this experiment?

A) 107

B) 1.07

C) 2.88

D) 81.1

E) 93.3

46) Sulfur and oxygen react to produce sulfur trioxide. In a particular experiment, 7.9 grams of SO3 are

produced by the reaction of 6.0 grams of O2 with 7.0 grams of S. What is the % yield of SO3 in this

experiment?

S (s) + O2 (g) → SO3 (g) (not balanced)

A) 48

B) 62

C) 73

D) 79

E) 92

3.4 Short Answer Questions

1) Complete and balance the following reaction, given that elemental rubidium reacts with elemental

sulfur to form Rb2S (s).

Na (s) + S (s) → ________

2) A compound was found to contain 90.6% lead (Pb) and 9.4% oxygen. The empirical formula for this

compound is ________.

3) The combustion of propane (C3H8) in the presence of excess oxygen yields CO2 and H2O:

C3H8 (g) + 5O2 (g) → 3CO2 (g) + 4H2O (g)

When 7.3 g of C3H8 burns in the presence of excess O2, ________ g of CO2 is produced.

52

4) Under appropriate conditions, nitrogen and hydrogen undergo a combination reaction to yield

ammonia:

N2 (g) + 3H2 (g) → 2NH3 (g)

A 9.3-g sample of hydrogen requires ________ g of N2 for a complete reaction.

5) Water can be formed from the stoichiometric reaction of hydrogen with oxygen:

2H2 (g) + O2 (g) → 2H2O (g)

A complete reaction of 5.0 g of O2 with excess hydrogen produces ________ g of H2O.

6) The combustion of carbon disulfide in the presence of excess oxygen yields carbon dioxide and sulfur

dioxide:

CS2 (g) + 3O2 (g) → CO2 (g) + 2SO2 (g)

The combustion of 15 g of CS2 in the presence of excess oxygen yields ________ g of SO2.

3.5 True/False Questions

1) The mass of a single atom of an element (in amu) is numerically equal to the mass in grams of 1 mole of

that element.

2) The molecular weight is always a whole-number multiple of the empirical formula weight.

3) A great deal of the carbon dioxide produced by the combustion of fossil fuels is absorbed into the

oceans.

4) The quantity of product that is calculated to form when all of the limiting reagent reacts is called the

actual yield.