Name: ……………………………………

Grade: …………10………………

Subject: Chemistry

Date: ……………….

Chapter 15 : Stoichiometry Practice Problems

Be sure to balance all equations before you start calculatingRally coach :

1) Lithium hydroxide reacts with hydrobromic acid to produce lithium bromide and water. If you start with 10 grams of lithium hydroxide, how many grams of lithium bromide will be produced? LiOH + HBr LiBr + H2O

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?

C2H4 + 3 O2 2 CO2 + 2 H2O

3) 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?

4) 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?

5) Given the following equation: LiOH + KCl LiCl + KOHa. I began this reaction with 20 grams of lithium hydroxide. What is my theoretical

yield of lithium chloride?b. I actually produced 6 grams of lithium chloride. What is my percent yield?

6) Given the following equation: C3H8 + O2 CO2 + H2Oa. If I start with 5 grams of C3H8, what is my theoretical yield of water?b. I got a percent yield of 75%. How many grams of water did I make?

7) Given the reaction: NaCl + CaO CaCl2 + Na2OWhat is my theoretical yield of sodium oxide if I start with 20 grams of calcium oxide?

8) FeBr2 + 2 KCl FeCl2 + 2 KBra. What is my theoretical yield of iron (II) chloride if I start with 34 grams of iron (II)

bromide?b. What is my percent yield of iron (II) chloride if my actual yield is 4 grams?

9) TiS + H2O H2S + TiOWhat 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?

Name: grade: date:

Mole & Mass Conversions

1. What is the mass (in grams) of 1.00 moles of copper atoms?1.00mol Cu x 63.5 g Cu = 63.5g Cu

1 mol Cu

2. How many moles are 4.00g of helium atoms?4.00g He x 1 mol He = 1.00 mol He

4.00 g He

3. What is the mass of 3.56 moles of zinc?3.56mol Zn x 65.4 g Zn = 233g Zn

1 mol Zn

4. What is the mass of 1.00 moles of water molecules?1.00mol H2O x 18.0 g H2O = 18.0g H2O

1 mol H2O

5. How many moles are found in 7.95g of lithium chloride?7.95g LiCl x 1 mol LiCl = 0.188 mol LiCl

42.4 g LiCl

6. What is the mass of 4.50mol of aluminum chloride?4.50mol AlCl3 x 134 g AlCl3= 603g AlCl3

1 mol AlCl3

7. Convert 250g of calcium hydroxide into moles.250g Ca(OH)2 x 1 mol Ca(OH)2 = 3.37 mol Ca(OH)2

74.1 g Ca(OH)2

8. You are given 365g of sugar (C6H12O6)a) How many moles would you have?

365g C6H12O6 x 1 mol C6H12O6= 2.03 mol C6H12O6

Answer Key

1) LiOH + HBr LiBr + H2OIf 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 H2OIf 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 + KOHa. I began this reaction with 20 grams of lithium hydroxide. What is my theoretical

yield of lithium chloride? 35.5 gramsb. 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 H2Oa. If I start with 5 grams of C3H8, what is my theoretical yield of water? 8.2 gramsb. 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 + Na2OWhat 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 KBra. What is my theoretical yield of iron (II) chloride if I start with 34 grams of iron (II)

bromide? 20.0 grams of FeCl2 b. What is my percent yield of iron (II) chloride if my actual yield is 4 grams? 20 %

9) TiS + H2O H2S + TiOWhat 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

Universal Children's Day

On December 14, 1954, the United Nations General Assembly recommended

that all countries should introduce an annual event from 1956 known as

Universal Children's Day to encourage understanding between children all

over the world and promoting the welfare of children.

It was recommended that individual countries should choose an appropriate

date for this occasion.

Many of the countries respected this recommendation and the Universal

Children's Day has since been annually observed on November 20.