1. The gram-formula mass of a compound is 48 grams.
The mass of 1.0 mole of this compound is –
A. 1.0 g
B. 4.8 g
C. 48 g
D. 480 g

Answer
C is the correct answer.

2. How many moles are in 59.6 grams of BaSO
4
?
A) 0.256 mole
B) 3.91 moles
C) 13.9 moles
D) 59.6 moles

Answer
A is the correct answer.

3. How many molecules are contained in 55.0 grams of
H2SO4?
A) 0.561 molecules
B) 3.93 molecules
C) 3.38 X 10 23 molecules
D) 2.37 X 10 24 molecules

Answer
C is the correct answer.

4. If a sample of magnesium has a mass of 60. grams, how many moles of magnesium does the sample contain?
A) 1.1 moles
B) 1.2 moles
C) 2.0 moles
D) 2.5 moles

Answer
D is the correct answer.

5. Analysis shows a compound to be, by mass, 43.8% N,
6.2% H, and 50.0% O. Which is a possible molecular formula for the compound?
A) NH
4
NO
2
B) NH
4
NO
3
C) NH
3
OH
D) N
2
OH

Answer
A is the correct answer.

6. A compound has an empirical formula of CH
2 a molecular mass of 180 grams. What is the
O and compound’s molecular formula?
A) C
3
H
6
O
3
B) C
6
H
12
O
6
C) C
6
H
11
O
7
D) C
12
H
22
O
11

Answer
B is the correct answer.

7. What is the percent by mass of iron in the compound Fe
2
O
3
?
A) 70 %
B) 56 %
C) 48%
D) 30 %

Answer
A is the correct answer.

8. What is the percent composition by mass of sulfur in the compound MgSO grams per mole)?
4
(gram-formula mass = 120.
A. 20%
B. 27%
C. 46%
D. 53%

Answer
B is the correct answer.

9. Given the balanced equation representing a reaction:
2H
2
+ O
2
→ 2H
2
O
What is the mass of H
2
O produced when 10.0 grams of
H
2 reacts completely with 80.0 grams of O
2
?
A. 70.0 g
B. 90.0 g
C. 180. g
D. 800. G

Answer
B is the correct answer.

10. Given two formulas representing the same compound:
Formula A Formula B
CH
3
C
2
H
6
CH
6
C
4
H
12
Which statement describes these formulas:
A. Formulas A and B are both empirical.
B. Formulas A and B are both molecular.
C. Formula A is empirical, and formula B is molecular.
D. Formula A is molecular, and formula B is empirical.

Answer
C is the correct answer.

11. The sum of the atomic masses of the atoms in one molecule of C
3
H
6
Br
2 is the–
A. formula mass
B. isotopic mass
C. percentage abundance
D. percentage composition

Answer
A is the correct answer.

12. The percent composition by mass of nitrogen in NH
4
(gram-formula mass = 35 grams/mole) is equal to –
OH
A. 4/35 X 100
B. 14/35 X 100
C. 35/14 X 100
D. 35/4 X 100

Answer
B is the correct answer.

13. Given the balanced equation representing a reaction:
2NaCl(ℓ) →2Na(ℓ) + Cl
2
(g)
A 1170. gram sample of NaCl(ℓ) completely reacts, producing 460. grams of Na(ℓ). What is the total mass of Cl
2
(g) produced?
A 355 g
B 710. g
C. 1420. g
D. 1630. g

Answer
B is the correct answer.

14. The gram-formula mass of NO
2 the mass of – is defined as
A. one mole of NO
2
B. one molecule of NO
2
C. two moles of NO
D. two molecules of NO

Answer
A is the correct answer.

15. Given the balanced equation representing a reaction:
CaO(s) + CO
2
(g) →CaCO
3
(s) + heat
What is the total mass of CaO(s) that reacts completely with 88 grams of CO
2 grams of CaCO
3
(s)?
(g) to produce 200.
A. 56 g
B. 88 g
C. 112 g
D. 288 g

Answer
C is the correct answer.

16. Which formula is both a molecular and an empirical formula?
A) C
6
H
12
O
6
B) C
2
H
4
O
2
C) C
3
H
8
O
D) C
4
H
8

Answer
C is the correct answer.