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Unit 4 Review

Total questions: 25

Worksheet time: 1hrs 15mins

Name
Class
Date
1.

What is the molar mass of (NH₄)₂CO₃?

a)

96

b)

44

c)

60

d)

84

2.

What is the total mass, in grams, of 0.75 mole of SO₂?

a)

48

b)

32

c)

64

d)

24

3.

What is the total number of moles represented by 20 grams of CaCO₃?

a)

0.2

b)

2.0

c)

0.5

d)

1.0

4.

What is the approximate mass of one mole of chlorine gas (Cl₂)?

a)

17.5 g

b)

35 g

c)

71 g

d)

71 mol

5.

Which of the following is the correct unit for the mass of one mole of a substance?

a)

N

b)

mol

c)

g

d)

m

6.

If the atomic mass of chlorine (Cl) is approximately 35, what reasoning explains why the mass of one mole of Cl₂ is about 71 g?

a)

Because Cl₂ is a compound of two different elements

b)

Because the mass of Cl₂ is double the atomic mass of Cl

c)

Because the atomic mass of Cl is rounded up

d)

Because Cl₂ contains one atom of chlorine

7.

What is the molar mass of potassium chloride, KCl?

a)

32.3 amu

b)

74.6 amu

c)

149.2 amu

d)

154.5 amu

8.

What is a mole in chemistry terms?

a)

a mammal found in Eurasia and North America

b)

an SI unit for measuring the amount of a substance

c)

a benign tumor sometimes found on human skin appearing as a small, sometimes raised area of skin, usually with darker pigment

d)

a Mexican sauce made from chili peppers, other spices, and chocolate

9.

What is the molar mass of carbon?

a)

6.0 g/mol

b)

12.0 g/mol

c)

22.4 g/mol

d)

6.02 x 10^23 g/mol

10.

Which of the following conversions is correct?

a)

1 mole of CO₂ = 44 grams of CO₂

b)

1 mole of NaCl = 58 grams of NaCl

c)

Both of the conversions are correct.

d)

Neither conversion is correct.

11.

Which of the following statements about a mole is incorrect?

a)

One mole of a substance always contains 6.022 x 10²³ particles.

b)

One mole of a substance always has the same mass, regardless of the substance.

c)

The mole is a standard unit in the International System of Units (SI).

d)

The number of particles in a mole is constant, but the mass of a mole depends on the substance.

12.

What is the approximate percent by mass of potassium in KHCO₃?

a)

39

b)

25

c)

50

d)

10

13.

What is the percent composition of carbon in acetic acid (CH₃COOH)?

a)

40.0%

b)

41.4%

c)

20.0%

d)

33.3%

14.

What is the molecular formula of a compound that has a molecular mass of 42 amu and an empirical formula of CH₂?

a)

C₄H₁₂

b)

C₂H₄

c)

C₃H₆

d)

CH₂

15.

The empirical formula of a compound is CH2. The molecular formula of this compound could be –

a)

C₃H₆.

b)

C₂H₆.

c)

CH₄.

d)

C3H₄.

16.

A compound has the empirical formula NO₂. Its molecular formula could be –

a)

N₄O₂.

b)

N₂O4.

c)

NO.

d)

N₄O₄.

17.

Which formulas could represent the empirical formula and the molecular formula of a given compound?

a)

CH₄, C₅H₁₂

b)

CH₂, C₃H₆

c)

CH₂O, C₄H₆O₄

d)

CHO, C₆H₁₂O₆

18.

Which formula is both a molecular and an empirical formula?

a)

C₄H₈

b)

C₃H₈O

c)

C₆H₁₂O₆

d)

C₂H₄O₂

19.

Calculate the molar mass of Mg(OH)2.

a)

33.2 g/mol

b)

41.3 g/mol

c)

86.9 g/mol

d)

58.3 g/mol

20.
What is the mass of 2 moles of propane (C3H8)?
a)
44 g
b)
88 g
c)
22 g
d)
13 g
21.

To melt the ice, Juan throws 455 g of calcium chloride, CaCl2 on his sidewalk. How many moles of CaCl2 did he throw?

a)

50,500 moles

b)

4.10 moles

c)

7.56 x 10-22 moles

d)

111 moles

22.
Which pair has the same empirical formula?
a)
NaCrO4 and Na2Cr2O7
b)
C2H4O2 and C6H12O6
c)
C3H6Oand C2H6O2
d)
CH4 and C2H6
23.
A chemical formula that shows the actual # and kinds of atoms present in one molecule of a compound is called_________
a)
ionic formula
b)
covalent formula
c)
empirical formula
d)
molecular formula
24.

Of the chemical formulas listed below, which formula is written in empirical formula?

a)

    P4O10

b)

    C5H11

c)

N2O4

d)

C6H18O3

25.
C6H12O6
a)
Empirical
b)
Molecular