Free Printable Percent Composition and Empirical Formula

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Percent Composition and Empirical Formula

Total questions: 25

Worksheet time: 1hrs 7mins

Name

Class

Date

A sample of a metal is 74% Aluminum. If the sample weighs 200 g, what is the mass of Aluminum in the sample?

74 g

200 g

148 g

100 g

An element sample is 44% Zinc. If the sample has a mass of 5.0 g, what the mass of the Zinc in the sample?

5.0 g

220 g

2.2 g

There is no Zinc

Find the percent composition of Cu₂S?

%Cu= 67.987 %S= 32.013

%Cu= 79.854 %S= 20.145

%Cu= 35.946 %S= 64.054

What is the percentage of oxygen in carbon dioxide? (CO₂)

27.3%

72.7%

30%

70%

What is the percentage of chlorine in sodium chloride? (NaCl)

60.7%

39.3%

60%

40%

What is the percentage of iron in iron(III)oxide (Fe₂O₃)?

30%

70%

40%

60%

Find the percentage composition of Mg in Mg₃(PO₄)₂.

27.48% Mg

43.11% Mg

16.00% Mg

12.63% Mg

What is the percent by mass of oxygen in MgO?

20%

40%

50%

60%

What is the percent by mass of fluorine in CaF₂(gram-formula mass = 78 g/mol)?

24%

49%

51%

65%

10.

What is the percent composition by mass of magnesium in the compound MgSO₄ (gram formula mass = 120 g/mol)?

20%

27%

46%

53%

11.

What is the percent composition by mass of oxygen in the compound MgSO₄ (gram formula mass = 120 g/mol)?

20%

27%

46%

53%

12.

In which compound is the percent composition by mass of Cl equal to 42%?

HClO (gram formula mass = 52 g/mol)

HClO₂ (gram formula mass = 68 g/mol)

HClO₃ (gram formula mass = 84 g/mol)

HClO₄ (gram formula mass = 100 g/mol)

13.

Which element in the compound potassium cyanide, KCN, has a percent composition of 60.97%?

None of the above

14.

What percentage of the total atomic mass of carbon monoxide (CO) is composed of carbon?

29%

43%

57%

73%

15.

A compound consists of 72.2% magnesium(Mg) and 27.8% nitrogen(N) by mass. What is the empirical formula?

Mg₄N₃

MgN₂

Mg₃N₂

MgN

16.

Which of the following is considered an empirical formula?

CH₃COOH

C₆H₁₂O₆

H₂O

17.

You are given the following percentages: 40.05% S and 59.95% O. Find the empirical formula for these elements.

SO2

SO3

SO4

18.

How many molecules are in 2.5 mol of NaCl?

1.5 x 10²⁴molecules

1.5 molecules

4.15 molecules

1.5 x 10²³molecules

19.

Which pair has the same empirical formula?

NaCrO₄ and Na₂Cr₂O₇

C₂H₄O₂ and C₆H₁₂O₆

C₃H₆O₃and C₂H₆O₂

CH₄ and C₂H₆

20.

A compound consists of 72.2% magnesium(Mg) and 27.8% nitrogen(N) by mass. What is the empirical formula?

Mg₄N₃

MgN₂

Mg₃N₂

MgN

21.

A formula with the lowest whole # ratio of elements in a compound is called

Molecular Formula

Chemical Formula

Empirical Formula

Distance Formula

22.

Glycerol has a molar mass of 92.09g/mol. Its percent composition is: 39.12% C, 8.75% H, and 51.12% O. What is the molecular formula for glycerol?

C₂H₃O₂

CH₂O

C₂H₄O₂

C₃H₈O₃

23.

2.40 g of an explosive, J, contains 0.473 g of nitrogen. J also contains 33.8% carbon and 1.41% hydrogen by mass. The remainder of J is oxygen.

What is the empirical formula of J?

C₄HNO₂

CH₂N₂O

C₂HNO₂

CHNO

24.

2.40 g of an explosive, J, contains 0.473 g of nitrogen. J also contains 33.8% carbon and 1.41% hydrogen by mass. The remainder of J is oxygen.

What is the empirical formula of J?

C₄HNO₂

CH₂N₂O

C₂HNO₂

CHNO

25.

What is the empirical formula for C₃H₈

C₃H₈

C₆H₁₆

CH_2.7

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Percent Composition and Empirical Formula

Total questions: 25

Worksheet time: 1hrs 7mins

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