Stoichiometry Practice Problems

Stoichiometry Practice Problems
Be sure to balance all equations before you start calculating! Answer key is at the end.

1. 
   Lithium hydroxide reacts with hydrobromic acid to produce lithium bromide and water. If you start with ten grams of lithium hydroxide, how many grams of lithium bromide will be produced?
   
   
   
2. 
   Ethylene (C₂H₄ ) reacts with oxygen gas to produce carbon dioxide and water. If you start with 45 grams of ethylene, how many grams of carbon dioxide will be produced?
   
   
   
3. 
   Given the equation: HCl + Na₂SO₄  NaCl + H₂SO₄
   If you start with 20 grams of hydrochloric acid, how many grams of sulfuric acid will be produced?
   
   
4. 
   Given the following equation: LiOH + KCl  LiCl + KOH
   
   1. 
      I began this reaction with 20 grams of lithium hydroxide. What is my theoretical yield of lithium chloride?
      
   2. 
      I actually produced 6 grams of lithium chloride. What is my percent yield?
      
      
5. 
   Given the following equation: C₃H₈ + O₂  CO₂ + H₂O
   
   1. 
      If I start with 5 grams of C₃H₈, what is my theoretical yield of water?
      
   2. 
      I got a percent yield of 75%. How many grams of water did I make?
      
      
6. 
   Be + 2 HCl  BeCl₂ + H₂
   My theoretical yield of beryllium chloride was 10.7 grams. If my actual yield was 4.5 grams, what was my percent yield?
   

7. 
   Given the reaction: NaCl + CaO  CaCl₂ + Na₂O
   What is my theoretical yield of sodium oxide if I start with 20 grams of calcium oxide?
   
   
8. 
   FeBr₂ + 2 KCl  FeCl₂ + 2 KBr
   
   1. 
      What is my theoretical yield of iron (II) chloride if I start with 34 grams of iron (II) bromide?
      
   2. 
      What is my percent yield of iron (II) chloride if my actual yield is 4 grams?
      
      
      
9. 
   TiS + H₂O  H₂S + TiO
   What is my percent yield of titanium (II) oxide if I start with 20 grams of titanium (II) sulfide and my actual yield of titanium (II) oxide is 22 grams?
   
   
   
10. 
    U + 3 Br₂  UBr₆
    What is my actual yield of uranium hexabromide if I start with 100 grams of uranium and 250 grams of bromine, and get a percent yield of 83% ?
    
11. 
    Sulfur dioxide can be produced in the laboratory by the reaction of hydrochloric acid and a sulfite salt such as sodium sulfite. (Na₂SO₃ + 2HCl  2NaCl + SO₂ + H₂O) What mass of SO₂ can be made from 25.0 g or Na₂SO₃ and 22.0 g of HCl?
    
    
    
12. 
    The rare earth metal terbium is produced from terbium (III) fluoride and calcium metal by the following single replacement reaction: 2TbF₃ + 3 Ca  3CaF₂ + 2Tb
    
    1. 
       Given 27.5 g of TbF₃ and 6.96 g of Ca, how many grams of terbium could be produced?
       
    2. 
       How many grams of the excess reactant is left over?
       

Answer Key

1. 
   LiOH + HBr  LiBr + H₂O
   If you start with ten grams of lithium hydroxide, how many grams of lithium bromide will be produced? 36.3 grams
   
   
   
2. 
   C₂H₄ + 3 O₂  2 CO₂ + 2 H₂O
   If you start with 45 grams of ethylene (C₂H₄), how many grams of carbon dioxide will be produced? 141.4 grams
   
   
   
3. 
   2 HCl + Na₂SO₄  2 NaCl + H₂SO₄
   If you start with 20 grams of hydrochloric acid, how many grams of sulfuric acid will be produced? 26.9 grams
   
   
   
4. 
   Given the following equation: LiOH + KCl  LiCl + KOH
   
   1. 
      I began this reaction with 20 grams of lithium hydroxide. What is my theoretical yield of lithium chloride? 35.5 grams
      
   2. 
      I actually produced 6 grams of lithium chloride. What is my percent yield? 16.9%
      
      
      
5. 
   Given the following equation: C₃H₈ + 5 O₂  3 CO₂ + 4 H₂O
   
   1. 
      If I start with 5 grams of C₃H₈, what is my theoretical yield of water? 8.2 grams
      
   2. 
      I got a percent yield of 75%. How many grams of water did I make? 6.1 grams
      
      
      
6. 
   Be + 2 HCl  BeCl₂ + H₂
   My theoretical yield of beryllium chloride was 10.7 grams. If my actual yield was 4.5 grams, what was my percent yield? 42.1 %
   
   
   
7. 
   Given the reaction: 2 NaCl + CaO  CaCl₂ + Na₂O
   What is my theoretical yield of sodium oxide if I start with 20 grams of calcium oxide?
   22.1 grams
   

8. 
   FeBr₂ + 2 KCl  FeCl₂ + 2 KBr
   
   1. 
      What is my theoretical yield of iron (II) chloride if I start with 34 grams of iron (II) bromide? 20.0 grams of FeCl₂
      
   2. 
      What is my percent yield of iron (II) chloride if my actual yield is 4 grams? 20 %
      
      
      
9. 
   TiS + H₂O  H₂S + TiO
   What is my percent yield of titanium (II) oxide if I start with 20 grams of titanium (II) sulfide and my actual yield of titanium (II) oxide is 22 grams? 137.5 % (theoretical yield is 16.0 grams—trick question; you should know that 100% is the highest yield possible)
   

10. 
    U + 3 Br₂  UBr₆
    What is my actual yield of uranium hexabromide if I start with 100 grams of uranium and 250 grams of bromine, and get a percent yield of 83% ? 250 grams UBr₆
    
    
    

11. 
    Sulfur dioxide can be produced in the laboratory by the reaction of hydrochloric acid and a sulfite salt such as sodium sulfite. (Na₂SO₃ + 2HCl  2NaCl + SO₂ + H₂O) What mass of SO₂ can be made from 25.0 g or Na₂SO₃ and 22.0 g of HCl? 11.3 grams SO₂
    
    
    

12. 
    The rare earth metal terbium is produced from terbium (III) fluoride and calcium metal by the following single replacement reaction: 2TbF₃ + 3 Ca  3CaF₂ + 2Tb
    
    1. 
       Given 27.5 g of TbF₃ and 6.96 g of Ca, how many grams of terbium could be produced? 18.4 grams Tb
       
    2. 
       How many grams of the excess reactant is left over? 2.4 grams TbF₃