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Worksheets

Empirical and Molecular Formulas

Total questions: 12

Worksheet time: 12mins

Name
Class
Date
1.

How many Carbons "C" are in C18H34O3

a)

18

b)

34

c)

3

d)

37

2.
What is the best definition for subscript?
 
a)

The big number that tells you the number of molecules.

b)

The atomic number

c)

The little number that tells the number of atoms for each element.

3.
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)
Mg3N
d)
MgN
4.

Molecular Formula = C2F6

Choose the correct empirical formula.

a)

CF

b)

C2F6

c)

C3F

d)

CF3

5.
Which pair has the same empirical formula?
a)
NaCrO4 and Na2Cr2O7
b)
C2H4O2 and C6H12O6
c)
C3H6Oand C2H6O2
d)
CH4 and C2H6
6.

Empirical Formula = CF2

Molecular formula mass = 192 g/mol

Molecular Formula = ?

a)

C4F8

b)

C8F4

c)

C3F6

d)

C2F4

7.

Molecular Formula = Si2F6

Choose the correct empirical formula.

a)

SiF

b)

Si2F6

c)

SiF3

d)

Si4F12

8.

How would you calculate the molar mass for C4H6?

a)

12.0111 + 1.00794

b)

4(12.0111) + 6(1.00794)

c)

2(12.0111) + 3(1.00794)

d)

6(12.0111) + 4(1.00794)

9.

The empirical formula of a substance is CH2O. The molar mass is 180g/mol. What is the molecular formula?

a)

CH2O

b)

C3H6O3

c)

C6H12O6

d)

C12H6O12

10.

What is the empirical formula of K2SO4?

a)

K2SO4

b)

KSO2

c)

K2SO2

d)

KSO8

11.
What is the empirical formula if you have 81.82% carbon and 18.18% hydrogen?
a)
C3H8
b)
CH4
c)
C2H2
d)
C4H10
12.
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