Chemistry 2202 Stoichiometry Unit Retest

Review Guide Chapter 2: The Mole Pgs. 42 – 77 You should be able to:

1. Define the term molar mass and calculate the molar mass of any given element or compound. (pg. 55)

2. Convert from moles to mass and mass to moles. 3. Do practice problems 16 – 27. Pgs. 57-60. 4. Convert # of particles moles mass and vice versa. 5. Do practice problems # 28 – 37, Pgs. 63-64 6. Do Section Review problems p. 65

Chapter 4: Quantities in Chemical Reactions. Pgs. 110-155

You should be able to: 1. Define the term stoichiometry. 2. Understand the general process for solving stoichiometric problems (pg. 124). 3. If given an amount (particles, mass or moles) of reactant in a chemical equation,

calculate: the amount (particles, mass or moles) of other reactants required amounts of products (particles, mass or moles) expected for that reaction. Assume the given reactant is limiting.

4. If given an amount (particles, mass or moles) of expected product in a chemical equation, calculate:

a. the amount (particles, mass or moles) of reactants required or b. amounts of other products (particles, mass or moles) expected for that

reaction. 5. Do problems 11-22, pgs. 121-126. 6. Define limiting reactant (reagent) and excess reactant (reagent). Pg. 129. 7. Identify the limiting and excess reagents in a given chemical reaction. 8. Do problems 23-26, pgs. 131. 9. Calculate the amount of excess reactant required to react with the limiting reactant. 10. Do Section Review problems 1-7, pgs. 135-136. 11. Calculate the expected yield of product (theoretical yield) in a chemical reaction

(based on the limiting reactant). 12. Do problems 27-30, pgs. 134-135. 13. Do Section Review problems 1-7, pgs. 135-136. 14. Define the terms actual yield, theoretical yield, and percent yield for a reaction (pg.

137-141) 15. Given two of: theoretical yield, actual yield and/or percent yield, calculate the

unknown quantity. 16. Do problems 31-33, pg. 139

Chapter 8: Solution Stoichiometry Pg. 280 - 313

1. Use the solubility table to determine if a solid is soluble in water (pg. 285) 2. Know that most oxides and sulfides are only slightly soluble or insoluble in water

(pg. 282) 3. Do problems 1-3, pg. 286. 4. Given the reactants, determine whether or not a reaction occurs in solution (pg. 289,

292). 5. Do problem #4, pg. 290 6. Write a dissociation equation for the dissolving of an ionic compound in water (pg.

299). 7. Given the amount of solute dissolved in a specified volume of solvent, calculate the

molar concentration of the solution (pg. 266-267) 8. Do problems 19-24, pg. 268 9. Calculate the concentration of ions in solution (pg. 300) 10. Do problems 7-10, pg. 300 11. Know and understand how to calculate required quantities of solids, gases, and/or

concentrations of solutions in mixed stoichiometry problems. 12. Do problems 15-22, pgs. 304 – 307 and problems 1-9 under section review pgs. 307-

308. 13. Perform the steps necessary to make a solution of known concentration. 14. Using the dilution equation, calculate the amount of solvent required to dilute a

given solution so that a desired concentration is achieved.

Formulas

n = cv

= 22.4 L/mol

ci vi = cf vf

Chemistry 2202 Stoichiometry Name __________________ 1. Mercury and oxygen react together to produce mercury oxide. What mass of

mercury oxide will be obtained from a reaction of 4.55 grams of oxygen and sufficient mercury?

2Hg(l) + O2(g) —> 2HgO3(s)

2. Sulfur and oxygen are used in the industrial production of sulfur dioxide. Assuming

that 0.800 litres of sulfur dioxide gas is produced, and the reaction is carried out at STP, what mass of sulfur was used?

S8(s) + 8O2(g) ----> 8SO2(g)

3. What mass of oxygen is produced when 2.30 grams of hydrogen peroxide is

decomposed into its individual elements? H2O2(g) ---> H2(g) + O2(g)

4. The antacid compound magnesium hydroxide will react with hydrochloric acid to neutralize excess stomach acid. What mass of magnesium hydroxide would be needed to neutralize 2.50 grams of the stomach acid(HCl(aq))? Mg(OH)2(aq)+2 HCl(aq)—>MgCl2+2HOH(l)

5. The Haber Process is based on nitrogen from the air reacting with hydrogen to

produce ammonia for use in fertilizers and dis-infecting cleaning solutions. N2(g) + 3H2(g) ----> 2NH3(g)

A. Providing there is sufficient hydrogen, what mass of nitrogen would be

needed would be needed to produce 65.0 grams of ammonia?

B. What mass of ammonia would be obtained from 2.85 grams of hydrogen, assuming there is sufficient nitrogen?

Chemistry 2202 Stoichiometry Show all workings. Name __________________ 1. Nitrogen and hydrogen are used in the industrial production of ammonia gas.

A. Write a reaction equation for this reaction.

B. Assuming that 0.400 moles of ammonia gas is produced, how many moles of nitrogen gas was used?

2. Aluminum and oxygen react together to produce aluminum oxide.

A. How many moles of aluminum are needed to form 2.30 moles of aluminum oxide?

B. How many moles of oxygen would be needed to react completely with 0.885 moles of aluminum?

C. How many moles of aluminum oxide would be produced when 17.5 moles of oxygen reacts with the hydrogen?

3. What mass of phosphorous is produced when 2.30 moles of diphosphorous

pentaoxide are decomposed into its individual elements?

4. The antacid compound magnesium hydroxide will react with hydrochloric acid to neutralize excess stomach acid.

A. Write a reaction equation for this reaction.

B. What mass of magnesium hydroxide would be needed to neutralize 2.50 grams of the stomach acid?

C. Assuming that all 2.50 grams of the stomach acid reacted, what mass of magnesium chloride would be produced?

5. The alchemist Paracelsus produced what is probably the first recorded observation

of the production of hydrogen gas from a reaction between iron and sulfuric acid.

A. Write a reaction equation for this reaction.

B. What mass of iron would be needed to react with 5.00 grams of the sulfuric acid?

C. What volume of hydrogen gas would be produced assuming the reaction took place under STP conditions?

Limiting Reagent Problems

1. 4.20 mol of CH3OH reacts with 8.75 mol of oxygen according to the equation:

2 CH3OH + 3 O2 ------> 2 CO2 + 4 H2O

a) Determine the limiting reagent.

b) What mass of CO2 is produced?

2. Hydrogen gas can be used to produce iron from the oxide Fe3O4 as shown in the

equation:

____Fe3O4(s) + ____H2(g) -----> ____Fe(s) + ____H2O(g)

If 0.0357 mol of Fe3O4 is placed in a container with 0.0269 mol of hydrogen gas, how much solid iron will be produced?

3. Given the equation: 4 Al(s) + 3 O2(g) -------> 2 Al2O3 (s)

a) Which chemical could NEVER be the limiting reagent?

b) If 1.25 mol of Al are placed in the reaction vessel with 1.10 mol of oxygen, how much Al2O3 wil be produced?

4. 2.50 mol of potassium iodide is reacted with 4.80 mol of silver nitrate. How many

moles of AgI will be produced?

5. Sodium chloride can be prepared by the reaction of sodium metal with chlorine gas. 2Na (s) + Cl2 (g) → 2 NaCl (s)

6.70 mol of Na (s) reacts with 3.10 mol of Cl2. a) Determine which reactant is the limiting reactant. b) How many moles of product are formed?

6. 58.0 g of calcium metal reacts with 58.0 g of chlorine gas. Determine the mass of CaCl2 (g) that will be formed.

7. 25 mL of 0.100 mol/L lead (II) nitrate solution reacts with 25 mL of 0.110 mol/L potassium nitrate solution. Find the mass of the precipitate.

Pb(NO3)2 (aq) + 2KI (aq) → PbI2 (s) + 2KNO3 (aq) 8. Part of the SO2 that is introduced into the atmosphere ends up being converted to

sulfuric acid, H2SO4. The net reaction is: 2 SO2(g) + O2(g) + 2 H2O(l) 2SO4(aq)

How much H2SO4 can be formed from 5.0 mol of SO2, 1.0 mol of O2, and an unlimited quantity of H2O?

9. Consider the following reaction: 2 Na3PO4(aq) + 3 Ba(NO3)2(aq) 3(PO4)2(s) + 6 NaNO3(aq)

Suppose that a solution containing 3.50 g of Na3PO4 is mixed with a solution containing 6.40 g of Ba(NO3)2. How many grams of of Ba3(PO4)2 can be formed?

10. A strip of zinc metal weighing 2.00 g is placed in an aqueous solution containing

2.50 g of silver nitrate, causing the reaction to occur. How many grams of silver will form?

11. Ethylene, C2H4(g) burns in air. How many grams of CO2 can form when a mixture of 2.93 g of C2H4 and 5.29 g of O2 is ignited?

12. What is the theoretical yield of calcium chloride when 52.1 g of calcium is allowed to

react with 78.1 g of chlorine?

Practice Problems - Solution Stoichiometry Answer ALL questions in space provided. Show ALL calculations.

1. A stock solution of sulfuric acid has a molar concentration of 17.6 mol/L. If 1.50 L of

2.00 mol/L sulfuric acid is needed for a high school lab, what volume of the stock sulfuric acid must be used?

2. Baking soda and lye can be combined for use as toilet bowl cleaner. What mass of

baking soda (NaHCO3) must be added to a 2.50 L bowl to prepare a 0.150 mol/L solution?

3. A. Balance the equation below.

____Cl2 + ____TiBr4 —> ____Br2 + ____TiCl4

b. Use the balanced equation to determine the volume of chlorine gas required to react with 2.85 moles of titanium (IV) bromide.

4. In a stoichiometry experiment, Millie Mole mixed solutions containing 19.50 g of sodium iodide and 1.50 g of lead (II) nitrate.

a. Write a balanced chemical equation for this reaction. b. Calculate the number of moles of each reactant. c. Identify the limiting reagent and excess reagent in the above reaction. d. Identify which of the two products will form a precipitate. e. Calculate the mass of the precipitate derived from the chemical reaction.

Chemistry 2202 Practice Problems– Concentrations, Dilution, Solution and Gas Stoichiometry

1. What is the molarity of the 438 mL solution which contains 0.245 moles KBr?

2. What volume in mL of 6.000 M Ca(NO3)2 solution contains 1.50 moles Ca(NO3)2?

3. What mass of NaCl are there in 142.1 mL of 2.000 M NaCl?

4. A 350.0 mL solution of 4.800 M H2SO4 is diluted to make a 3.200 M H2SO4 solution. What is the volume of the diluted solution?

5. A 0.345g sample of silver phosphate is dissolved to form 100mL of aqueous solution. What is the concentration of the silver ions in the solution?

6. Calculate the mass of precipitate formed when 50.0mL of a 0.123mol/L magnesium chloride solution reacts with excess silver nitrate.

7. Natural gas is mainly methane, CH4. What mass of methane must be burned to produce 56.0 L of carbon dioxide gas at STP?

8. Calculate the volume of carbon dioxide gas that should be produced when 12.5 kg of octane (assume C8H18) is completely burned in a snowmobile engine. Assume STP conditions

9. One of the reactions that leads to the formation of acid rain in the atmosphere occurs between sulfur dioxide gas, that often comes from the burning of fossil fuels, with oxygen gas which naturally exists in the atmosphere.

2SO2(g) + O2(g) 2SO3(g) Assuming STP conditions, calculate the volume of oxygen gas that is consumed in the production of 80.0 L of sulfur trioxide gas.