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Molecular Weight/ % Mass/ Empirical Formulas and Balancing RXNS

Total questions: 22

Worksheet time: 2hrs 50mins

Name
Class
Date
1.

What is the molecular weight of Ca3(PO4)2

a)

310 g/mol

b)

296.6 g/mol

c)

342 g/mol

d)

225 g/mol

2.
What is the molar mass NaCl?
a)
58 grams
b)
22.95 grams
c)
162 grams
d)
6.02 x 1023
3.

What is the molar mass of Ca(NO3)2?

a)

148.096 g

b)

164.086 g

c)

102.055 g

d)

70.084 g

4.

Calculate the molar mass for Al(OH)3

a)

78.0 g/mol

b)

72 g/mol

c)

28 g/mol

d)

25 g/mol

5.

What is the percent by mass of Oxygen in water? H2O.

a)

33 %

b)

88.9%

c)

11.1%

d)

50%

6.

What is the percent by mass of Carbon in sugar C12H22O11 ?

a)

144.0

b)

42.1

c)

12.01

d)

342.0

7.

The formula of a compound having the smallest whole-number ratio of atoms in the compound is called ____?

a)

Chemical Formula

b)

Empirical Formula

c)

Mass formula

d)

Ideal formula

8.

What would the percent by mass be of Oxygen in a compound that has a formula of C10H18O ?

a)

154.0

b)

77.9

c)

10.4

d)

11.7

9.

What is the empirical Formula of an unknown compound that is 18.8% sodium, 29.0% chlorine and 52.2% Oxygen?

Hint *(Don't forget to assume a 100 gram sample)

a)

NaClO

b)

Na2Cl2O3

c)

NaClO4

d)

NaClO3

10.

What is the empirical formula for a compound that is 40% Carbon, 6.70% Hydrogen and 53.3% oxygen?

Hint*(remember to assume 100 g sample)

a)

CHO

b)

CH2O

c)

CH3O

d)

CH2O2

11.

Quinone, which is used in the dye industry and in photography, is an organic compound containing only C, H, and O. What is the empirical formula of the compound if you find that 0.105 g of the compound gives 0.257 g of CO2 and 0.0350 g of H2O when burned completely? Given a molecular weight of approximately 108 g/mol, what is its molecular formula?

a)

CHO

b)

C2H4O8

c)

C6H4O2

d)

C3H2O

12.

Balance the following:

____ Fe + ____ Cl2 → ____ FeCl3

a)
1,1,2
b)
1,3,1
c)
2,2,3
d)
2,3,2
13.

Which type of reaction is:

2 NaBr + Ca(OH)2 → CaBr2 + 2 NaOH

a)
Synthesis
b)
Single Displacement
c)
Double Displacement
d)
Combustion
14.
Which type of reaction is: C2H4 + 3 O2 → 2 CO2 + 2 H2O
a)
Synthesis
b)
Decomposition
c)
Single Displacement
d)
Combustion
15.

Which type of reaction is:

2 H3AsO4 → As2O5 + 3 H2O

a)
Synthesis
b)
Decomposition
c)
Single Displacement
d)
Combustion
16.

Which type of reaction is:

3 Pb + 2 H3PO4 → 3 H2 + Pb3(PO4)2

a)
Synthesis
b)
Single Displacement
c)
Double Displacement
d)
Combustion
17.

Balance this reaction:

____ Na3PO4 + ____ KOH ---> ____ NaOH + ____ K3PO4

a)

1,3,3,1

b)

1,3,2,1

c)

2,3,3,1

d)

1,1,3,1

18.

Balancing this reaction:

____ CH4 + ____ O2 ---> ___ CO2 + ____ H2O

a)

2,1,3,1

b)

1,2,1,2

c)

1,2,2,1

d)

2,1,1,2

19.

Balance this reaction:

____ NaF + ____ Br2 ---> ___ NaBr + ____ F2

a)

3,1,2,1

b)

1,2,3,4

c)

2,1,2,1

d)

1,2,1,2

20.

Balance this reaction:

____ RbNO3 + ____ BeF2 ----> ____ Be(NO3)2 + ____ RbF

a)

1,1,1,1

b)

1,2,1,1

c)

2,1,1,2

d)

2,1,2,1

21.
Which of these is a synthesis reaction?
a)

H2 +02-->H202

b)

CH4 + O2 --> CO2 + H2O

c)

H2O2 --> H2+ O2

d)

2Na + CaCO3 --> Ca + Na2CO3

e)

CuNO3 + CaCO3 --> CuCO3 + CuNO3

22.
__BF3 + __Li2SO3 --> __B2(SO3)3 + __LiF
a)
2,3,1,3
b)
2,3,1,6
c)
4,4,2,12
d)
3,3,1,9