Stoichiometry - Barrington High School



Stoichiometry

It’s all about the…

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Honors Chemistry

Re: 12/2011

Mole Town Madness

Cu + 2 AgNO3 --------> 2 Ag + Cu(NO3)2

1a. Name the products:

b. Name the reactants:

2. Determine the molar mass for the following:

a. Cu b. AgNO3 c. Ag d. Cu(NO3)2

3. How many moles of silver are produced when 5.3 moles of copper reacted?

4. How many moles of silver nitrate are needed to completely react with 0.045 moles of copper?

5. How many moles of copper (II) nitrate are produced when 1000.00 grams of silver are produced?

6. How many grams of copper are needed to produce 14.2 moles of silver?

7. How many grams of copper (II) nitrate are produced when 5.0 moles of silver are also produced?

8. How many moles of silver are produced when 10.0 grams of copper react?

9. How many grams of silver nitrate are needed to completely react with 8.5 grams of copper?

10. How many grams of silver are produced from 1.9 moles of copper?

The Never Ending Dream

Cu(s) + 4 HNO3(aq) --> Cu(NO3)2(aq) + 2 NO2(g) + 2 H2O(l)

1a. Name the reactants:

b. Name the products:

2. Calculate the molar mass, molecular weight in grams.

a. Cu b. HNO3 c. Cu(NO3)2 d. NO2 e. H2O

3. Determine the number of moles of NO2 formed when 8.65 moles of copper react.

4. How many moles of copper reacted if 16.3 moles of copper(II)nitrate are formed?

5. How many moles of water are produced from 102 grams of nitric acid?

6. If 12.2 moles of copper react, how many grams of copper(II) nitrate are produced?

7. How many grams of nitric acid are needed to react with 2.35 grams of copper?

8. How many grams of nitrogen dioxide are produced from 3.78 moles of nitric acid?

9. How many moles of copper are needed to produce 67.9 grams of nitrogen dioxide?

10. How many grams of copper (II) nitrate are produced with 3.40 moles of water?

Limiting Reactants in a Cookie Recipe

What is a limiting reactant in a chemical reaction?

The limiting reactant sets a limit on the amount of product that can be produced.

What are the limiting reactants in a cookie recipe?

The ingredient or ingredients that limit the amount of cookies that can be made.

Ingredients ("Materials"):

• 0.5 cup sugar

• 0.5 cup brown sugar

• 1 & 1/3 stick margarine

• 1 egg

• 0.5 tsp salt

• 1 tsp vanilla

• 0.5 tsp baking soda

• 1.5 cups flour

• 1 & 1/3 cup chocolate chips

Directions ("Procedure"):

1. Mix sugars and margarine together until smooth.

2. Add egg, salt, and vanilla and mix well.

3. Stir in baking soda, flour, and chocolate chips. Chill for best results.

4. Make dough into balls 3 cm in diameter; place on ungreased cookie sheet.

5. Bake at 350oF for about 10 minutes, until pale brown. Makes 24 chocolate chip cookies.

Questions & Calculations:

Suppose you have only the following materials:

• 1 dozen eggs

• 4 fluid ounces of vanilla

• 1 pound of salt

• 1 pound of baking soda

• 3 cups of chocolate chips

• 5 pounds of flour

• 1 pound of margarine

• 5 pounds of sugar

• 2 pounds of brown sugar

1. For each ingredient, calculate how many batches could be prepared if all that ingredient were used up. Use the recipe equivalents listed below. (For example, based on the 12 eggs available, at 1 egg per batch, 12 batches are possible.) SHOW ALL WORK & USE FACTOR LABEL METHOD!!!

2. To determine the limiting reactants, identify the ingredient(s) that will produce the fewest batches.

3. How many batches can be produced from these materials?

Recipe Equivalents:

1 lb. margarine = 4 sticks 1 lb. brown sugar = 2 & 1/4 cups 1 lb. sugar = 2 cups

1 ounce liquid = 2 tablespoons 12 ounces salt = 1 cup 16 ounces = 1 lb.

1 tablespoon = 3 teaspoons 1 cup = 48 teaspoons

1 lb. flour = 4 cups 1 lb. baking soda = 1 & 1/4 cups

Stoich

Honors Chemistry

OH NO! IT’S BACK JUST LIKE A BAD DREAM

WRITE and BALANCE the equations first before you CALCULATE the problem. BE SURE TO INCLUDE ALL UNITS and SHOW ALL WORK!!

1. Magnesium reacts with oxygen to produce magnesium oxide.

a. How many moles of oxygen are necessary to completely react with 7.5 moles of magnesium?

b. When 50.2g of magnesium is combined with 40.8g of oxygen:

1. How many grams of magnesium oxide should be produced.

2. What is the limiting reactant?

3. What is the excess reactant?

4. How many grams are in excess?

c. When the experiment in b was performed, there were 70.35 g of magnesium oxide produced. Determine the percent yield.

2. Dicarbon hexahydride burns in oxygen to produce carbon dioxide and water.

a. How many grams of C2H6 are necessary to burn in order to produce 0.25 moles of water?

b. How many grams of CO2 are theoretically produced from 62.30 grams of oxygen?

c. If there were 44.2g CO2 actually produced in the reaction in b, determine the

percent yield.

3. Lead(II) nitrate reacts with sodium iodide in a double replacement reaction.

a. How many moles of lead (II) nitrate are necessary to react with 100.0 grams of sodium iodide?

b. How many moles of lead (II) iodide are produced with 2.3 moles of sodium nitrate?

c. When 2.5 moles of lead(II) nitrate are mixed with 4.3 moles of sodium iodide, 1. What mass of lead iodide is theoretically produced?

2. Determine the limiting reactant.

3. Determine the number of moles of excess reactant.

4. Sodium reacts with water to produce sodium hydroxide and hydrogen gas.

a. What mass of hydrogen is produced when 50.0 grams of sodium react?

b. How many grams of water need to react to produce 235.0 grams of sodium hydroxide?

5. Aluminum reacts with copper(II) sulfate in a single replacement reaction.

a. How many grams of copper are theoretically produced from 6.2 moles of CuSO4

mixing with 3.0 moles of aluminum?

b. What is the limiting reactant.

c. Which reactant is in excess and by how many grams?

d. Determine the percent yield of the experiment above actually produced 250. g of copper.

6. The decomposition of hydrogen peroxide into water and oxygen.

a. How many grams of hydrogen peroxide are needed to produce 6.5 moles of oxygen?

b. How many moles of water are produced with 3.2 moles of oxygen?

7. Write the equation for the synthesis of diphosphorus pentoxide:

a. When 25.0g of phosphorus and 40.0g of oxygen are placed in a container what

mass of diphosphorus pentoxide should be produced?

b. If 44.3 g of diphosphorus pentoxide are actually produced in the experiment

above, what is the percent yield?

c. How many grams of phosphorus are needed to react with 6.52 moles of oxygen?

Stoich Review c12 Honors

Chapter 12 Stoich Review

1. Na3N + 3 AgNO3 ---> Ag3N + 3 NaNO3

a. What mass of sodium nitrate is formed from the complete reaction of 20.0 g Na3N?

b. How many moles of silver nitride are produced from 5.76 g of silver nitrate?

c. How many grams of silver nitride are produced from 2.3 moles of silver nitrate?

d. What number of nitrogen atoms is in the Ag3N formed in c?

2. Zn + Cu(NO3)2---> Cu + Zn(NO3)2

If 100. g of zinc metal and 100. g of copper(II) nitrate react:

a. What number of grams of copper are produced?

b. Which reactant is in excess?

c. How much in excess?

3. 2Mg + O2 --- 2MgO

a. Burning 20.0 g of magnesium produces 32.5 g of solid product. Determine the number of moles of magnesium reacted.

b. What is the percent yield of this reaction?

4. 2C + 2H2O ---> CH4 + CO2

a. If 25.0g of carbon react with excess water. How many grams of methane can be expected if the percent yield is 90.0%

5. CH4 + 4Cl2 ---> CCl4 + 4HCl

When 35.0g CH4 react with 150. g Cl2:

a. What is the limiting reactant?

b. Which reactant is in excess and by how much?

c. What is the actual yield in moles if the percent yield of carbon tetrachloride is 75.4%?

6. Acid rain can form from the combustion of nitrogen gas to produce HNO3 in water. If a car burns 425g of N2, how many moles of HNO3 can be produced as acid rain?

N2 + 2O2 --->2NO2

3NO2 + H2O ---> 2HNO3 + NO

7. A student burns 250. g of naphthalene, C10H8, in 500. g of O2. The mass of CO2 produced is 500. g.

C10H8 + 12 O2 ---> 10 CO2+ 4H2O

a. Determine the number of moles of oxygen put into the system.

b. What is the limiting reactant?

c. Which reactant is in excess? How much is in excess?

d. What is the percent yield of the carbon dioxide?

8. Name the following compounds:

a. MgO e.SnO2

b. SO3 f. CoCO3

c. CO2 g. OCl2

d. FeCl2 h. NO2

9. Write the formulas for the following compounds:

a. lead (IV) dichromate b. aluminum persulfate

c. dichlorine trioxide d. dinitrogen monoxide

e. cadmiun acetate f. ammonium oxalate

10. Silver nitrate reacts with aluminum. The following data is obtained.

mass of aluminum (initial) 1.09g

mass of aluminum (final) 0.62g

mass of silver nitrate + vial 14.63g

mass of empty vial 5.76g

mass of mass of silver + beaker 71.42g

mass of beaker 65.79g

a. Determine the number of moles of aluminum reacted.

b. Determine the number of moles of silver nitrate reacted.

c. Determine the number of moles of silver formed.

d. What is the mole ratio of silver to aluminum?

e. What is the mole ratio of silver to silver nitrate?

f. Balance the equation for the reaction

g. Which reactant is in excess?

h. What mass is in excess?

11. When analyzing lab data how do you determine which reactant is excess and which reactant is limiting?

Mole Town Madness Answers Oh No! It's Back Just Like a Bad Dream

2 a. 63.5 g/mole 1 a. 3.8 moles

b. 169.9 g/mole b. 1. 83.3 g

c. 107.9 g/mole b. 2. Magnesium

d. 187.9 g/mole b. 3. Oxygen

3. 11 moles b. 4. 7.7 g

4. 0.090 moles c. 84.5 %

5. 4.634 moles 2. a. 2.5 grams

6. 451 grams b. 49.0 grams

7. 468.75 g, w/ SF 470 grams c. 90.2 %

8. 0.315 moles 3. a. 0.3336 moles

9. 45 grams b. 1.2 moles

10. 410 grams c. 1. 9991.1 grams, w/ SF 990 grams

c. 2. NaI

The Never Ending Dream c. 3. 0.3 moles

2. a. 63.5 g/mole 4. a. 2.2 grams

b. 63.0 g/mole b. 106 grams

c. 187.5 g/mole 5. a. 285.75 grams, w/ SF 290 grams

d. 46.0 g/mole b. Aluminum

3. 17.3 moles c. w/ SF 270 grams of copper (II) sulfate

4. 16.3 moles d. 86 %

5. 0.810 moles 6. a. 442 grams, w/ SF 440 grams

6. 2,287.5, w/ SF 2,290 grams b. 6.4 moles

7. 9.33 grams 7. a. 57.3 grams

8. 86.9 grams b. 77.3 %

9. 0.738 moles c. 162 grams

10. 319 grams

Stoichiometry Review Review Answers Continued…

1. a. 61.4 grams 6. 20.2 moles

b. 0.0113 moles 7. a. 15.6 moles

c. 259 grams, w/ SF 260 grams b. oxygen

d. 4.6 x 1023 atoms c. 83 grams naphthalene

2. a. zinc d. 87.3 %

b. 65 grams 8. & 9. ask if you have questions

c. 33.9 grams 10. a. 0.017 moles

3. a. 0.823 moles b. 0.0522 moles

b. 97.9 % c. 0.0522 moles

4. 15 grams d. 3:1

5. a. chlorine e. 1:1

b. 26.6 grams methane in excess g. & h. aluminum, 0.62 grams

c. 0.398 moles 11. ask if you have questions

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