Here are three examples of "gimme" questions from last summer's third exam. All three are questions about gases that you could probably predict would also be covered by your exam this term. Get out some scrap paper and see how fast you can do these questions (as if this was the exam) then come back and record and explain your answers. Note: Even though numerical answers are required, you shouldn't need a calculator to answer the first two questions.

What is the answer to the question? Explain how you arrived at the answer.

What is the answer to the question? Explain how you arrived at the answer.

What is the answer to the question? Explain how you arrived at the answer.

How do you think you did? Good, I hope. If you struggled much to solve these problems, you should probably review the appropriate sections in the text and work some more problems.

The first question was about the relationship between P and T for a fixed amount of gas when the volume is constant. If you didn't cruise through this question, you should revisit Section 8.6, worked example 8.3 and problem 8.7 in the text.

The second question was about the "molar volume" of an ideal gas at STP: 1 mole of an ideal gas occupies 22.4 L at standard temperature and pressure (22.4L/mol at STP). This useful bit of information will be found in the given information on the front of your exam. If you weren't sure what to do with this question, make sure you review Section 8.8 and work through questions 8.64 and 8.67 at the end of the chapter.

The third question was a classic example of a PV=nRT calculation. You can be sure that something like this will be on your exam. If this wasn't easy for you, make sure you look over Section 8.9 in the text. Worked examples 8.6 and 8.7 and question 8.76 will be good practice on this type of problem.

Here are a few more questions that cover facts, concepts or calculations that are critical to success on the third exam. Your answers for these questions should be short and quick. Make sure to look up the answers and review the topic if you lack confidence on any of the following questions.

An exothermic reaction is one that (absorbs/releases) heat, in other words, heat is a (product/reactant).

A spontaneous reaction is one that has a ______ value for DG.

If DS is positive, did disorder increase or decrease in the reaction?

If the pressure on a gas is tripled, what will happen to its volume? (Assume fixed n and T.)

Name the three types of intermolecular forces. Name a simple molecule that can do all three. What is its shape?

What is the definition of molarity?

What volume of solute is needed to prepare 100 mL of a solution that is 12% (v/v)?

Rank the following aqueous solutions in order of increasing boiling point. (For example, A<B<C if C had the highest b.p., B was in the middle and A had the lowest b.p.)

A: 0.5 M cesium phosphate

B: 0.8 M potassium nitrate

C: 0.6 M sodium sulfate

If you struggled with any of these questions, make sure you also review related material–not just the version asked here. For example, think about ALL of the ways that we describe endothermic and exothermic reactions.

For example: An endothermic reaction is one where:

• heat is a reactant

• heat is absorbed

• DH > 0

• DH is a positive number

Keep studying hard! You can get the gimmes, and when you do, you will do better on the whole exam!

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