1. #32 A compound is formed when 9.03 grams Mg combines with
3.48 grams N. What is the percent
composition of this compound?
The total weight is: = 12.51
The percentage of Mg is: x 100 = 72.2 %
12.51
The percentage of N is: x 100 = 27.8 %
12.51

2. #33 When a 14.2 g sample of mercury (II)
oxide is decomposed into its elements
by heating, 13.2 g Hg is obtained. What
is the percent composition of the
compound?
The total weight is: grams
The percentage of Hg is: x 100 = 93.0 %
14.2
The percentage of O is: x 100 = 7.0 %
14.2
The difference between
the beginning and end weight is the oxygen

3. #34 Calculate the percent composition of these compounds.
a. ethane (C2H6)
The total molar mass of ethane is:
(12.0 x 2) + (1.0 x 6) 30.0 g/mole
The percentage of C is: x 100 = 80.0%
30.0
The percentage of H is: 6.0 x 100 = 20.0 %
30.0

4. 120.1 120.1 120.1 120.1 #34 Calculate the percent composition
of these compounds.
b. sodium bisulfate (NaHSO4)
The total molar mass of (NaHSO4 is:
(16.0 x 4)= g/mole
The percentage of Na is: x 100 = 19.2%
120.1
The percentage of H is: 1.0 x 100 = .83%
120.1
The percentage of S is: x 100 = 26.7 %
120.1
The percentage of O is: x 100 = 53.3 %
120.1

5. 17.0 80.0 #35 Calculate the percent nitrogen in these fertilizers.
a. NH3
The total molar mass of (NH3 is:
(1.0 x 3)= 17.0 g/mole
The percentage of N is: x 100 = 82.4%
17.0
b. NH4NO3
The total molar mass of NH4NO3 is:
14.0+(1.0 x 4)+14+(16 x 3)= 80.0
g/mole
The percentage of N is: x 100 = 35.0 %
80.0
Two nitrogens