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STOICHIOMETRY REVIEW ANSWERS
• 1. The calculation of quantities in chemical equations is called
• Stoichiometry
• 2. The first step in most stoichiometry problems is to convert given quantities to
• Moles
• 3. When two substances react to form products, the reactant which is used up is called the
• Limiting Reagent
• 4. The amount of product that forms when a reaction is carried out in the laboratory is the
• Actual Yield
• 5. The maximum amount of products that could be formed from given amounts of reactants is the
• Theoretical Yield
• 6. When an equation is used to calculate the amount of product that will form during a reaction, then the value obtained is called the
• Theoretical Yield
• 7.
2Al(s) + 3Pb(NO3)2(aq) 2Al(NO3)3(aq) + 3Pb(s) • A.) 2 moles Al + 3 molecules Pb(NO3)2 2 molecules Al(NO3)3 + 3 moles Pb
• F
• B.) 2 grams Al + 3 grams Pb(NO3)2 2 grams Al(NO3)3 + 3 grams Pb
• F
• C.) 2 moles Al + 3 moles Pb(NO3)2 2 moles Al(NO3)3 + 3 moles Pb
• T
• 8. In every chemical reaction ___________ stay the same.• The Mass
• 9. In the reaction 2CO + O2 2CO2, what is the ratio of moles of oxygen used to moles of CO2 produced?
• 1:2
• 10. For C5H12 + 8O2 5CO2 + 6H2O
• ______ moles of reactants chemically change into ______ moles of product.
• 9 moles of reactant to 11 moles of product
11. How many moles of oxygen are required to react completely with
14.8 mol Al when given 4Al + 3O2 2Al2O3?
14.8 mol Al x -----------------4 mol Al
3 mol O2
= 11.1 mol O2
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12. Given the balanced equation 16HCl + 2KMnO4 2KCl + 2MnCl2 + 5Cl2 + 8H2O
if 2.0 mol of KMnO4 reacts, how many moles of H2O are produced?
8.0 mol H2O
13. Based on…16HCl + 2KMnO4 2KCl + 2MnCl2 + 5Cl2 + 8H2O
…how many grams of KCl are produced when 3.0 mol of KmnO4 reacts?
3.0 mol KMnO4 x ----------------2 mol KMnO4
2 mol KClX ---------------------
1 mol KCl
74.5 g KCl= 220 g KCl
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14. If CuO + H2 Cu + H2O, how many moles of H2O are produced
when 240 grams of CuO react?
240 g CuO x ----------------80 g CuO
1 mol CuOX ---------------------
1 mol CuO
1 mol H2O= 3.0 mol H2O---------
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------------------
15. In the reaction Zn + H2SO4 ZnSO4 + H2
how many grams of H2SO4 are required to produce
2.3 gram of H2?
2.3 g H2 x -----------------
2 g H2
1 mol H2
x ------------------- x -------------------
1 mol H2
1 mol H2SO4
1 mol H2SO4
98 g H2SO4
113 g H2SO4
=-----------------
----------------
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-----------
-------
-------
16. LiOH + HBr LiBr + H2OIf you start with 15.0 grams of
lithium hydroxide, how many grams of lithium bromide will be produced?
54.4 g LiBr
17. How many molecules of oxygen are required to react completely with 2.96 X 1023 molecules Al when given 4Al + 3O2 2Al2O3?
2.96 x 1023 molecules Al x -----------------4 molecules Al
3 molecules O2
=
2.22 x 1023 molecules O2
----------------------
----------------------
18. How many molecules of oxygen are produced by the
decomposition of 6.54 g of potassium chlorate (KClO3)?
2KClO3 2KCl + 3O2
6.54 g KClO3 x --------------- x --------------- x ------------------ =122.5 g KClO3
1 mol KClO3
2 mol KClO3
3 mol O2
1 mol O2
6.02 x 1023 molecules O2
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4.82 x 1022 molecules O2
• 19. LiOH + KCl LiCl + KOH
• A) I began this reaction with 20 grams of lithium hydroxide.
What is my theoretical yield of lithium chloride?
Convert 20 grams of LiOH Grams of LiCl
35 g LiCl• B) I actually produced 6 grams of lithium
chloride. What is my percent yield?
Actual_________
Theoretical X 100 = 17%
• 20. C3H8 + 5 O2 3 CO2 + 4 H2O
• A) If I start with 5 grams of C3H8, what is my theoretical yield of water?
Convert 5 grams C3H8 Grams of H2O
8.2 g H2O• B) I made 6.1 g of water. What was my percent
yield?
Actual_________
Theoretical X 100 = 74%
21. 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?
Actual___Theoretical
= 42%X 100
22. CaSO4 + NaI CaI2 + Na2SO4
If 34.7 g of calcium sulfate and 58.3 g of sodium iodide are placed in a reaction vessel, what will be the
limiting reagent?
NaINote: Refer to Limiting Reagent Notes to see how to work it out.
