Name: ______Date: ______
HON Chemistry – Unit 8/9 Review
For this unit test, you will need to be able to:
- explain what happens during a chemical reaction.
- complete a BCA table in order to determine how much of each reactant is used up and/or how much
product is formed.
- complete a BCA table to determine the theoretical yield of a product & then calculate the percent yield
when given an actual yield.
- determine the limiting reactant, which reactant is in excess, and how much excess is left when given
amounts of each reactant involved in a reaction.
- determine a balanced equation, a theoretical yield, an actual yield, and a percent yield based on lab data.
- use the ideal gas law to determine a missing variable (pressure, volume, temperature, or # of moles).
- determine either the volume or # of moles of a gas at STP using the molar volume of a gas (22.4 L/1 mole)
- determine the molarity of a solution when given grams and a volume or determine a volume when given
the molarity of solution and use molarity to complete a BCA table.
Chemical Reactions – Stoichiometry
1. Nitrogen gas reacts with hydrogen gas to form ammonia gas, or NH3. Write the balanced equation below:
a. True or False: The balanced equation shows the number of atoms is conserved.
b. True or False: The balanced equation shows the number of molecules is conserved.
c. Given the picture below where the striped circles = nitrogen, and the open circles = hydrogen, draw what the resulting products would look like.
d. What is the limiting reactant? ______
e. How many excess reactant molecules are left? ______
2. Nitrogen monoxide reacts with oxygen gas to produce nitrogen dioxide. If 0.66 g of nitrogen monoxide were reacted excess oxygen, how many grams of nitrogen dioxide would be formed? Complete a BCA table. Make sure to label all units & identify your answer.
3. Phosphorus trichloride reacts with water to produce phosphorous acid, H3PO3 and hydrochloric acid, HCl. How many moles are phosphorus trichloride are needed to react completely with 123 g of water?
Percent Yield
4. Aluminum metal reacts with copper (II) sulfate to produce solid copper and aqueous aluminum sulfate. If 1.85 g of Aluminum is reacted with excess copper (II) sulfate, what is the theoretical yield of copper. If you actually obtain 10.8 g of copper, what is your percent yield?
Limiting Reactants
5. Hydrazine, N2H4 , reacts with dinitrogen tetroxide to produce nitrogen gas and water. If 10.5 g of hydrazine react with 12.4 g of dinitrogen tetroxide, what is the limiting reactant? How many grams of the excess reactant will be left over?
Lab data
6. When a student places a piece of magnesium ribbon into lead (II) nitrate, lead metal and aqueous magnesium nitrate is produced. A large strip of magnesium ribbon was placed into the lead (II) nitrate solution, and left to react overnight. The following day, there was still some strip of magnesium left, and the following data was collected:
Mass of beaker: 108.55 g
Mass of beaker + lead: 130.15 g
Mass of Magnesium before reaction: 6.50 g
Mass of Magnesium after reaction: 3.86 g
Determine the percent yield of lead. Show all work below!
Molar volume and gas stoichiometry
The following equations/constants will be useful for the next section:
Molar Volume of a Gas @ STP = 22.4 L/mol Ideal Gas Law: PV = nRT
or
7. Four different balloons contains 8.00 g each of O2, CO2, and SO2 at STP. Calculate the volume of each balloon. Which balloon would be the largest, and why?
8. Nitrogen gas and hydrogen gas combine to produce ammonia gas (NH3). What volume of hydrogen gas at STP would be required to react with 10.0 g of nitrogen gas?
9. Consider the following reaction: Aluminum oxide decomposes into aluminum metal and oxygen gas. What volume of oxygen gas at 32°C and 0.975 atm is produced when 4.32 g of aluminum oxide is decomposed?
10. On space ships, lithium hydroxide is used to help get rid of carbon dioxide. The lithium hydroxide reacts with carbon dioxide gas to form lithium carbonate and water. How many grams of lithium hydroxide are needed to remove all of the carbon dioxide from the enclosed space of a spaceship that has a volume of 2.10 x 105 L if the partial pressure of carbon dioxide is .00793 atm and the temperature is 23°C?
Molar concentration
11. What mass of Na2CO3 is needed to prepare 1.25 L of a 0.75M solution?
12. What is the molarity of the solution if a whole box of Morton’s salt (737g) is dissolved in a 2 L soda bottle of distilled water?
13. Calcium carbonate (“limestone”) reacts with hydrochloric acid according to the following balanced equation:
1 CaCO3(aq) + 2 HCl(aq) à 1 CO2(g) + 1 CaCl2(aq) + 1 H2O(l)
a. What mass of calcium carbonate is needed to make 1.2 liters of a 1.7 M calcium carbonate solution?
b. What volume of 3.0 M hydrochloric acid is needed to completely react with the amount of calcium carbonate in Part 12a above?
c. Based on Parts 2a and 2b above, how many grams of water would be produced?
Modeling Chemistry 1 U8 review v2.0