Chemical Engineering Chapter 6 One mole of potassium sulfate contains

36) One mole of potassium sulfate contains:

A) 4 moles of oxygen.

B) 2 moles of sulfur.

C) 1 mole of potassium.

D) 3 moles of potassium.

E) none of the above

37) How many moles of carbon are in 3.5 moles of calcium carbonate?

A) 10.5

B) 3.5

C) 7

D) 100.09

E) none of the above

38) How many moles of fluorine are in 3.2 moles of xenon hexafluoride?

A) 22.4

B) 12.8

C) 19.2

D) 16

E) none of the above

39) If a sample of carbon dioxide contains 3.8 moles of oxygen atoms, how many moles of

carbon dioxide are in the sample?

A) 1.9

B) 3.8

C) 7.6

D) 11.4

E) none of the above

40) A 15.5 gram sample of diphosphorous pentoxide contains how many grams of phosphorous?

A) 3.38

B) 1.69

C) 6.76

D) 13.5

E) none of the above

41) A 42.7 gram sample of potassium nitrate contains how many grams of potassium?

A) 39.1

B) 16.5

C) 21.4

D) 8.54

E) none of the above

42) An iron ore sample is found to be 35.00% Fe by mass. How many grams of ore are needed to

obtain of Fe?

A) 1297

B) 158.9

C) 295.1

D) 350.0

E) none of the above

43) A 500. gram iron ore sample was determined to contain 242 grams of iron. What is the mass

percent of iron in the ore?

A) 93.7

B) 48.4

C) 51.6

D) 32.6

E) none of the above

44) Bauxite is an ore that contains the element aluminum. If you obtained 108 grams of

aluminum from an ore sample that initially weighed 204 grams, what is the mass percent of

aluminum in this bauxite ore?

A) 52.9

B) 15.6

C) 0.53

D) 47.1

E) none of the above

45) What is the mass percent of hydrogen in water?

A) 33.3

B) 88.8

C) 5.60

D) 11.2

E) none of the above

46) What is the mass percent of chlorine in hydrochloric acid?

A) 2.8

B) 35.5

C) 97.2

D) 70.1

E) none of the above

47) What is the mass percent of carbon in oxalic acid, H2C2O4?

A) 2.24

B) 13.3

C) 26.7

D) 34.5

E) none of the above

48) Which of the following compounds has the highest mass percent of “O”?

A) MnO

B) MnO2

C) Mn2O3

D) Mn3O2

E) none of the above

49) Which of the following statements about empirical formulas is incorrect?

A) An empirical formula represents a molecule.

B) An empirical formula gives the smallest whole number ratio of each type of atom in a

molecule.

C) An empirical formula must be multiplied by an integer to obtain the molecular formula.

D) The molecular formula can be the same as the empirical formula in some situations.

E) All statements are correct.

50) The empirical formula of a compound:

A) describes the mass relationships in a molecule.

B) is the same as the molecular formula.

C) indicates the structure of the molecule.

D) indicates the simplest ratio of atoms in the compound.

E) none of the above

51) The simplest formula for hydrogen peroxide is HO. To determine its molecular formula, it is

necessary to know:

A) the properties of hydrogen peroxide.

B) the density of hydrogen peroxide.

C) the molar mass of hydrogen peroxide.

D) the number of moles of hydrogen peroxide in 1.00 g of the substance.

E) none of the above

52) Which of the following is already in its empirical formula?

A) C22H34O10

B) C6H6

C) C6H12O3

D) C5H12O2

E) none of the above

53) The chemical formula CH2O can be classified as:

A) molecular only.

B) empirical only.

C) empirical, possibly molecular.

D) not enough information

E) none of the above

54) A chromium oxide compound contains 104.0 grams of chromium and 48.0 grams of oxygen.

What is the most likely empirical formula of this compound?

A) CrO

B) CrO2

C) CrO3

D) Cr2O3

E) Cr3O2

55) An iron chloride compound contains 55.85 grams of iron and 106.5 grams of chlorine. What

is the most likely empirical formula for this compound?

A) FeCl

B) FeCl2

C) Fe2Cl

D) FeCl3

E) Fe3Cl

56) A 7.96 gram sample of silver reacts with oxygen to form 8.55 gram of the metal oxide. What

is the formula of the oxide?

A) AgO

B) AgO2

C) Ag2O

D) Ag3O

E) none of the above

57) Determine the empirical formula of a compound containing 60.3% magnesium and 39.7%

oxygen.

A) MgO

B) MgO2

C) Mg2O3

D) Mg2O

E) none of the above

58) Determine the empirical formula of a compound containing 83% potassium and 17.0%

oxygen.

A) KO

B) KO2

C) K2O3

D) K2O

E) none of the above

59) Vitamin C is known chemically by the name ascorbic acid. Determine the empirical formula

of ascorbic acid if it is composed of 40.92% carbon, 4.58% hydrogen, and 54.50% oxygen.

A) CHO

B) CH2O

C) C2H3O2

D) C3H4O3

E) none of the above

60) Determine the correct empirical formula of a compound containing 26.68% carbon, 2.24%

hydrogen, and 71.08% oxygen.

A) CHO

B) CHO2

C) C0.5H0.5O1

D) C2H2O4

E) none of the above

61) A compound composed of only carbon and hydrogen is 25.2% hydrogen by mass. The

empirical formula for this compound is:

A) CH 0.25

B) C3H

C) CH4

D) C2H8

E) none of the above

62) What is the molecular formula of a compound given the molar mass of the compound is

and the empirical formula is C2H7?

A) C4H14

B) C3H21

C) C2H7

D) C2H14

E) none of the above

63) An estrogen compound with the empirical formula C12H17O2 has a molecular mass of

386.6 g/mol. What is the value of n necessary to find the molecular formula?

A) 0.2

B) 1

C) 2

D) 20

E) none of the above

64) What is the value of n when the empirical formula is C3H5 and the molecular mass is

?

A) 0.02

B) 5

C) 10

D) 140

E) none of the above

65) What would the empirical formula be for the molecular compound C6H9O4?

A) C2H3O2

B) CH3O2

C) C3H6O2

D) C3H9O4

E) none of the above

66) What is the molecular formula of a compound given the molar mass of the compound is

30.04 gram and the empirical formula is NH?

A) NH

B) N2H2

C) N2H6

D) N4H4

E) none of the above

67) A compound has a molar mass of 180.18 g/mol. Given the following percent composition,

calculate the molecular formula: 39.99% C, 6.73% H, 53.28% O.

A) CH3O2

B) CH2O

C) C3H6O3

D) C6H12O6

E) none of the above

68) An unknown acid has a molar mass of 60.06 g/mol. Given the following percent

composition, what is the molecular formula? .

A) C3H4O3

B) CH2O

C) C2H4O2

D) C6H12O6

E) none of the above

69) A compound composed of only hydrogen and oxygen is 5.94% hydrogen by mass. The

molar mass of this compound is 34.02 g/mol. What is the compound’s molecular formula?

A) 34.02

B) H2O2

C) HO

D) H6O

E) none of the above

Algorithmic Questions

1) Bananas cost 33¢ per pound. If you spent $0.77, how many pounds of bananas did you

purchase?

A) 2.33

B) 1.73

C) 0.429

D) 2.01

E) none of the above

2) How many atoms are present in 4.5 moles?

A)

B)

C)

D)

E) none of the above

3) If you have atoms of copper, how many moles of copper do you have?

A) 0.250

B) 4.00

C) 0.600

D) 3.00

E) none of the above

4) How many moles of potassium are in 156.4 g?

A) 39.10

B) 4.000

C) 0.2500

D) 5.050

E) none of the above

5) What is the mass of sulfur atoms?

A) 208

B) 4.93

C) 155

D) 32.07

E) none of the above

6) How many atoms of lithium are in 18.7 g?

A)

B)

C)

D)

E) none of the above

7) What is the mass (in grams) of 1.95 moles of water ?

A) 18.02

B) 9.24

C) 35.1

D) 6.022 × 10 23

E) none of the above

8) What is the mass (in grams) of 3.03 × 1024 molecules of carbon dioxide molecules?

A) 221

B) 0.114

C) 1.33

D) 44.01

E) none of the above

9) How many moles of oxygen are in 3.30 moles of NaC ?

A) 3.30

B) 0.303

C) 19.0

D) 13.2

E) none of the above

10) Given that sodium chloride is 39.0% sodium by mass, how many grams of sodium chloride

are needed to have of Na present?

A) 2.44

B) 0.371

C) 2,430

D) 37.1

E) none of the above

11) What is the mass percent of Na in sodium chloride?

A) 58.4

B) 60.7

C) 39.3

D) 47.5

E) none of the above

12) What is the mass percent of oxygen in sodium oxide?

A) 37.1

B) 25.8

C) 74.2

D) 62.0

E) none of the above