Free Printable Empirical and Molecular Formulas

1.

Which pair has the same empirical formula?

a)

NaCrO₄ and Na₂Cr₂O₇

b)

C₂H₄O₂ and C₆H₁₂O₆

c)

C₃H₆O₃and C₂H₆O₂

d)

CH₄ and C₂H₆

2.

What is the molecular formula if the empirical formula is CH₂O and the molecular molar mass is 180.18?

a)

CH₂O

b)

C₂H₄O₂

c)

C₄H₈O₄

d)

C₆H₁₂O₆

3.

Which of the following could be a molecular formula with the empirical formula of CH₂O?

a)

CH₂O₂

b)

CHO

c)

C₃H₅O₃

d)

C₂H₄O₂

4.

If a compound has an empirical formula of $C_2H_5$ and a molecular weight of 58 g/mol, what is its molecular formula?

a)

$C_2H_5$

b)

$C_3H_8$

c)

$C_4H_{10}$

d)

$C_5H_{12}$

5.

What is the main difference between an empirical formula and a molecular formula?

a)

Empirical formulas show the exact number of atoms of each element in a molecule.

b)

Molecular formulas show the simplest whole-number ratio of atoms in a compound.

c)

Empirical formulas show the simplest whole-number ratio of atoms in a compound.

d)

Molecular formulas are always the same as empirical formulas.

6.

Given the molecular formula $C_6H_{12}O_6$ , what is the empirical formula?

a)

$C_6H_{12}O_6$

b)

$CH_2O$

c)

$C_3H_6O_3$

d)

$C_2H_4O_2$

7.

What is the empirical formula of a compound that contains 40% carbon, 6.7% hydrogen, and 53.3% oxygen by mass?

a)

$CH_2O$

b)

$C_2H_4O_2$

c)

$C_3H_6O_3$

d)

$CH_3O$

8.

Which of the following is an example of an empirical formula?

a)

$C_6H_{12}O_6$

b)

$CH_2O$

c)

$H_2O_2$

d)

$C_2H_4$

9.

If the empirical formula of a compound is $CH_2$ and its molecular weight is 56 g/mol, what is the molecular formula?

a)

$C_2H_4$

b)

$C_3H_6$

c)

$C_4H_8$

d)

$C_5H_{10}$

10.

A compound has an empirical formula of $NO_2$ and a molecular weight of 92 g/mol. What is its molecular formula?

a)

$NO_2$

b)

$N_2O_4$

c)

$N_3O_6$

d)

$N_4O_8$

11.

Which of the following is a correct example of an empirical formula?

a)

$C_6H_{12}O_6$

b)

$C_2H_4O_2$

c)

$CH_2O$

d)

$C_3H_6O_3$

12.

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

a)

Mg₄N₃

b)

MgN₂

c)

Mg₃N₂

d)

MgN

13.

Given the following: 42.07% Na, 18.89% P, and 39.04% O, determine the empirical formula.

a)

NaPO2

b)

Na2PO3

c)

Na3PO4

d)

NaPO4

14.

What is the molecular formula for a compound with the empirical formula: K₂SO₄and a molecular mass of 696g.

a)

K₂SO₄

b)

K₈SO₁₆

c)

K₈S₄O₈

d)

K₈S₄O₁₆

15.

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

a)

Molecular Formula

b)

Chemical Formula

c)

Empirical Formula

d)

Distance Formula

16.

What is the empirical formula for N₂S₃?

a)

NS

b)

N₃S₂

c)

N₂S₃

d)

N₁S_1.5

17.

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

18.

How many Carbons "C" are in C₁₈H₃₄O₃

a)

18

b)

34

c)

3

d)

37

19.

Which one is an empirical formula?

a)

H₂O₂

b)

C₂H₆O₁₂

c)

CaCl₂

d)

N₂O₈

20.

Which of these is NOT an empirical formula?

a)

CH2

b)

C2H5

c)

C6H4

d)

C3H7

e)

C5H17

21.

What is the empirical formula of K₂SO₄?

a)

K₂SO₄

b)

KSO₂

c)

K₂SO₂

d)

KSO₈

22.

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

a)

SO

b)

SO2

c)

SO3

d)

SO4

23.

Choose the correct empirical formula...

a)

CF

b)

C₂F₆

c)

C₆F₂

d)

CF₃

24.

Which of the following compounds has the same empirical formula as its molecular formula?

a)

$C_2H_4$

b)

$C_6H_{12}O_6$

c)

$H_2O$

d)

$C_4H_8$

25.

A compound has an empirical formula of $CH_2$ and a molecular weight of 84 g/mol. What is its molecular formula?

a)

$C_2H_4$

b)

$C_3H_6$

c)

$C_4H_8$

d)

$C_6H_{12}$

Empirical and Molecular Formulas

Total questions: 25

Worksheet time: 25mins

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