affected by the addition of heat? (B) does—it says that the average speed of
gas molecules increases as heat (thermal energy) is added to the system and
decreases as heat is taken away from a system. The answer to question 1 is
(B).
If you know the ideal gas law (covered in Chapter 8), you would simply
look among the answer choices for one of the variables from the equation,
PV = nRT. In this equation, P = pressure, V = volume, n = number of moles
of gas, R = the ideal gas constant, and T = temperature. Volume is the
variable listed among the answer choices, so the correct answer is (D).
- You should associate vapor pressure with the degree to which a liquid
will evaporate at a temperature that’s below its normal boiling point—and
lo and behold, this is similar to how you’ve paraphrased choice (E):
volatility. The answer is (E). - Read the question, and then look at the answer choices. Which of the
choices, when stated in your words, mentions a characteristic of a gas that
depends on its formula but not its temperature? Well, choice (C) looks like
the most likely—the weight of a gas molecule does depend on its identity
(formula) but not on its temperature. None of the other answer choices
make any sense, so choose (C).