Mole Practice Test printable pdf download

Mole Practice Test

Mole Practice Test [Answer on a separate sheet.]

1. What is an empirical formula? The lowest whole number ratio of a

compound.

2. Which of the following are empirical formulas? H

O, H

, C

, CH

3. Convert this molecular formula into an empirical formula. C

4. What is the percent composition of Hydrogen in C

? Show work.

C = 12.01 X 5 = 60 g H = 1.0079 X 10 = 10

60 / 70 = 86% 10/70 = 14%

5. A compound is found to contain 63.52 % iron and 36.48 % sulfur. Find its

empirical formula. Show your work.

63.52 g X 1 mole/55.85 g = 1.14 moles

36.48 g X 1 mole/32.06 g = 1.14 moles

Fe = 1.14 moles/1.14 moles = 1 mole Fe

S = 1.14 moles/1.14 moles = 1 mole S

= FeS

6. In the laboratory, a sample is found to contain 1.05 grams of nickel and

0.29 grams oxygen. Determine the empirical formula. Show your work.

1.05 g Ni X 1 mole/58.69 g Ni = .018 moles

0.29 g O X 1 mole/15.99 g O = .018 moles

Ni .018/.018 =1

.018/.018 = 1

=NiO

7. A compound is 85.7 % carbon and 14.3 % hydrogen. Calculate the empirical formula.

85.7 g C X 1 mole/12.011 g C = 7.14 moles

14.3 g H X 1 mole/1.0079 g H = 14.30 moles

C = 7.14/7.14 = 1 mole C

H = 14.30/7.14 = 2 moles H

=CH

8. A 68 g sample of a liquid is found to contain 4 g of Hydrogen and 64 g of Oxygen. What is

the percent composition of H= 4g/68g = .059 = 5.9%H

O= 64/68 .94 = 94% O

Is this compound water? NO How do you know? Empirical Formula is HO

What is the empirical formula for this liquid? HO Show your work.

4 g H X 1 mole H/1 g = 4 moles H

64 g O X 1 mole / 16 g = 4 moles O

Mole Practice Test