CLASS SET
Stoichiometry Practice
(Selected Answers are given in bold)
Mole to Mole Problems
1. N
2 +
3H
2
→ 2NH
3
How many moles of hydrogen are needed to completely react with 2.0 moles of nitrogen?
2. 2KClO
3
→ 2KCl + 3O
2
How many moles of oxygen are produced by the decomposition of 6.0 moles of potassium chlorate?
3. Zn + 2HCl → ZnCl
2
+ H
2
How many moles of hydrogen are produced from the reaction of 3.0 moles of zinc with an excess of hydrochloric acid?
3 moles
4. C
3
H
8
+ 5O
2
→ 3CO
2
+ 4H
2
O
How many moles of oxygen are necessary to react completely with 4.0 moles of propane (C
3
H
8
)?
K
3
PO
4
+ Al(NO
3
)
3
→ 3KNO
3
+ AlPO
4
How many moles of potassium nitrate are produced when 2.0 moles of potassium phosphate react with two moles of
aluminum nitrate? 6 moles
Mass to Mass Problems
1. 2KClO
3
→ 2KCl + 3O
2
How many grams of potassium chloride are produced if 25g of potassium chlorate decompose? 15 g
2. N
2
+ 3H
2
→ 2NH
3
How many grams of hydrogen are necessary to react completely with 50.0 g of nitrogen in the above reaction?
3. How many grams of ammonia, NH
3,
are produced in the reaction in Problem 2? 60.7 g
4. 2AgNO
3
+ BaCl
2
→ 2AgCl + Ba(NO
3
)
2
How many grams of silver chloride are produced from 5.0 g of silver nitrate reacting with barium chloride? 4.3 g
5. How much barium chloride is necessary to react with the silver nitrate in Problem 4? 3.1 g
Molarity and Stoichiometry Problems
1. NaCl + KOH → KCl + NaOH
How many liters of 0.2 M KOH are required to produce 25 g of KCl? 1.7 L
2. 2AgNO
3
+ CaCl
2
→ Ca(NO
3
)
2
+ 2AgCl
If 250 mL of 0.5M AgNO
3
are added to CaCl
2
, how many grams of AgCl will be produced? 17.9 g
3. 3CsBr + Al(OH)
3
→ AlBr
3
+ 3CsOH
If 25 g of AlBr
3
was produced when 125 mL of a CsBr solution was added, what was the molarity of the CsBr solution?
2.3 M
4. How many mL of 0.5 M CsBr are required to produce 100 g of CsOH? (Use the balanced equation in problem 3). 1340
mL
Mixed Stoichiometry Problems
1. How many moles of H
2
would be required to completely react with O
2
to produce 5 moles of water? 5 mol H
2
2. H
2
SO
4
+ NaOH → Na
2
SO
4
+ H
2
O
a. Balance this equation
b. What mass of H
2
SO
4
would be required to react with 0.75 mol of NaOH? 37g
3. What mass of NO
2
is formed when NO reacts with 384 g of O
2
? 1104g (Balanced equation is: 2NO + O
2
→
→→
→ 2NO
2
)
4. If 30 g of H
2
SO
4
reacts with aluminum hydroxide in a double replacement reaction, what mass of water is produced?
11.0g (Balanced equation is: 3H
2
SO
4
+ 2Al(OH)
3
→
→→
→ Al
2
(SO
4
)
3
+ 6H
2
O)
5. Tin(II) fluoride, SnF
2
, is used in some toothpastes. It is made by the reaction of tin with hydrogen fluoride according to
the following equation.
Sn + 2HF → SnF
2
+ H
2
How many grams of SnF
2
are produced from the reaction of 30 g of HF with Sn? 118 g
6. In a spacecraft, the carbon dioxide exhaled by astronauts can be removed by its reaction with lithium hydroxide, LiOH,
according to the following chemical equation.
CO
2
(g) + 2LiOH(s) → Li
2
CO
3
(s) + H
2
O(l)
If 1.20x10
24
molecules of CO
2
is exhaled, the average amount exhaled by a person each day, how much (in grams)
Li
2
CO
3
(s) is produced? 148g Li
2
CO
3
7. When 9.8g of aluminum oxide decomposes, how many grams of aluminum metal are produced?
(Hint: You must criss-cross to get the formula for aluminum oxide.) 5.2 g Al (Balanced equation is: 2Al
2
O
3
→
→→
→ 4Al +
3O
2
)
8. How many grams of iodine are produced when 0.72 mol of fluorine react with potassium iodide?
(Hints: You must criss-cross to get the formula for potassium iodide. Check to see if iodine and fluorine are diatomic.
Iodine is not the only product; you must figure the other product out before balancing this equation.) 182.9 g (Balanced
equation is: 2Na + 2H
2
O →
→→
→ 2NaOH + H
2
)
9. How many grams of sodium are required to react with water to produce 5.0g of sodium hydroxide? (Unbalanced
equation is: Na + H
2
O → NaOH + H
2
) 2.9 g
10. How many molecules of H
2
are produced in the reaction in #9? 3.76x10
22
molecules of H
2