4th Partial: Homework 1

I. Read the following chapters: Stoichiometry and Gases (on the gases chapter focus on the section that pertains to the Ideal Gas Law, make sure you look through the rest of the chapter as well). Take notes to compliment the notes you took in class. II. Solve the following problems. Show all of your work. Be neat and orderly otherwise it will cost you deductions. If I can’t find your answer OR I don’t understand your work the WHOLE question will be wrong. Make sure you show units (2 points off for every unit that is not shown). HOMEWORK IS DUE TUESDAYNOVEMBER 22nd, 2011.

1. The reaction between solid sodium and iron (III) oxide is one in a series of reactions that inflates an automobile airbag: Na (s) + Fe2O3 (s) Na2O (s) + Fe (s). If 100 g of Na and 100 g of Fe2O3are used in this reaction, determinethe following.

a. Limiting reactant b. Excess reactant c. Mass of solid iron produced d. Mass of excess reactant that remains after the reaction is

complete. (HINT: after determining the limiting and excess reactants. Do a mass to mass conversion of the amount of product produced to the excess reactant… this will be the amount of excess reactant you used. Then subtract that amount from your original reactant).

2. When copper wire is placed into a silver (I) nitrate solution, silver crystals and copper (II) nitrate solution form.

a. Write the balanced chemical equation for the reaction. b. If a 20.0-g sample of copper is used, determine the

theoretical yield of silver. c. If 60.0-g of silver is recovered from the reaction,

determine the percent yield of the reaction. d. How many particles of silver are present in the product?

4th Partial: Homework 1

3. To produce 15.4 L of nitrogen dioxide at 310 K and 2.0 atm, how much many liters of nitrogen gas and oxygen gas are required? (HINT: remember Avogadro’s principle from the problems in class).

4. The gas acetylene, often used for welding, burns according to the following equation.

2C2H2 (g) + 5O2 (g) 2H2O + 4CO2 (g) If you have a 10.0-L tank of acetylene at 25oC and 1.00 atm pressure, how many moles of CO2 will be produce if you burn ALL the acetylene in the tank? How many particles of CO2 will be present?

5. When iron rusts, it undergoes a reaction with oxygen to form iron (III) oxide.

4Fe (s) + 3O2 (g) 2Fe2O3 (s) Calculate the volume of oxygen gas at STP that is required to completely react with 52.0 g of iron. What is the volume of 1 moles of gas at STP? (HINT: look at the problems in class for specifications on STP).

EXTRA CREDIT CHALLENGE (will only be graded if the rest of the homework is done): An excess of acetic acid is added to 28 g of sodium bicarbonate at 25oC and 1 atm pressure. During the reaction, the gas cools to 20oC. What volume of carbon dioxide will be produced? The balanced equation for the reaction is shown below. NaHCO3 (aq) + CH3COOH (aq) NaCH3COO (aq) + CO2 + H2O