Stoichiometry 

1. What is the mass of one mole of acetylsalicylic acid (aspirin), C

9

H

8

O

4

?  

a.

29 g  

b.

108 g  

c.

196 g  

d.

180. g  

e.

none of the above  

2. Determine the number of moles of aluminum in 2.154 x 10

-1

 kg of Al.  

a.

5816 mol  

b.

7.984 mol  

c.

6.02 x 10

23

 mol  

d.

4.801 mol  

e.

8.783 mol  

3. How many grams of zinc are there in 22.7 g of ZnCl

2

?  

a.

0.35 g  

b.

0.17 g  

c.

10.9 g  

d.

1476 g  

e.

0.32 g  

4. A compound with a composition of 87.5 % N and 12.5 % H was recently discovered. 
What is the empirical formula for this compound?  

a.

NH

2

b.

N

2

H

3

c.

NH  

d.

N

2

H

2

e.

N

2

H  

5. This equation is unbalanced: PCl

3

 + H

2

O 

→

 H

3

PO

3

 + HCl When it is correctly 

balanced, the coefficients are, respectively  

a.

1,3,1,1  

b.

1,1,1,3  

c.

1,3,1,3  

d.

2,3,2,3  

e.

none of the above