1. A 28. 0g Sample of nitrogen gas combines completely with 6
A 28.0g Sample of nitrogen gas combines completely with 6.0g of hydrogen gas to form ammonia. What is the mass of ammonia formed?
A 22.0g Sample of nitrogen gas combines completely with 9.0g of hydrogen gas to form ammonia. What is the mass of ammonia formed?
ANSWERS
= 34.0g
= 31.0g

2. If 45. 98g of sodium combines with chlorine gas to form 116
If 45.98g of sodium combines with chlorine gas to form g of sodium chloride, what mass of chlorine gas is used in the reaction?
If 43.97g of sodium combines with chlorine gas to form g of sodium chloride, what mass of chlorine gas is used in the reaction?
ANSWERS
X =
X = g
X =
X = 70.89g

3. When burning 180g of glucose in the presence of 192g of oxygen, water and carbon dioxide are produced. If 108g of water is produced, how much carbon dioxide is produced?
When burning 185g of glucose in the presence of 187g of oxygen, water and carbon dioxide are produced. If 104g of water is produced, how much carbon dioxide is produced?
ANSWERS
= X
= X
264g = X
= X
= X
268g = X

4. A 25. 3g sample of an unknown compound contains 0. 8g of oxygen
A 25.3g sample of an unknown compound contains 0.8g of oxygen. What is the percent by mass of oxygen in the compound?
A 29.1g sample of an unknown compound contains 0.9g of oxygen. What is the percent by mass of oxygen in the compound?
ANSWERS
(0.8/25.3) x 100
= 3%
(0.9/29.1) x 100
= 3%

5. Magnesium combines with oxygen to form magnesium oxide. If 10
Magnesium combines with oxygen to form magnesium oxide. If 10.67g of magnesium reacts completely with 6.83g of oxygen, what is the percent by mass of oxygen in magnesium oxide?
Magnesium combines with oxygen to form magnesium oxide. If 10.57g of magnesium reacts completely with 6.96g of oxygen, what is the percent by mass of oxygen in magnesium oxide?
ANSWERS
= 17.53
(6.96/17.53) x 100
= 39.7%
= 17.50
(6.83/17.50) x 100
= 39.0%

6. When mercury oxide is heated, it decomposes into mercury and oxygen
When mercury oxide is heated, it decomposes into mercury and oxygen. If 28.4g of mercury oxide decomposes, producing 2.0g of oxygen, what is the percent by mass of mercury in mercury oxide?
When mercury oxide is heated, it decomposes into mercury and oxygen. If 28.9g of mercury oxide decomposes, producing 2.5g of oxygen, what is the percent by mass of mercury in mercury oxide?
ANSWERS
2.0 + X = 28.4
X = 26.4
(26.4/28.4) x 100
= 93.0%
2.5 + X = 28.9g
X = 26.4
(26.4/28.9) x 100
= 91.3%

7. Two unknown compounds are analyzed.
Compound I contains 5.63 g of tin and 3.37 g of chlorine, while Compound II contains 2.50 g of tin and 2.98 g of chlorine.
Find the relative mass of tin in the compounds.
ANSWERS
Mass of Tin
Mass of Cl
Mass Tin/mass Cl I
5.63 g
3.37 g II
2.50 g
2.98 g
1.67
.839
I/II =
1.67/.839
= 2

8. Two unknown compounds are analyzed.
Compound I contains g of iron and g of oxygen, while Compound II contains g of iron and g of oxygen.
Find the relative mass of iron in the compounds.
ANSWERS
Mass of Fe
Mass of O
Mass Fe/Mass O I
52.46 g
22.54 g II
25.19 g
32.47 g
.7757
2.327
I/II =
2.327/.7757
= 3