shown in Figure 2. The pressure values in a 3 L vessel should therefore be greater than those
of the 4 L vessel but less than those of the 2 L vessel. In the 2 L vessel, 10 g of NO 2 gives a
pressure of approximately 2,000 mmHg. In the 4 L vessel, 10 g of NO 2 gives a pressure of
approximately 1,000 mmHg. Therefore, in a 3 L vessel, 10 g of NO 2 should give a pressure
between 1,000 and 2,000 mmHg, as in (G).
33 . A Temperature is not mentioned in either figure, but the passage indicates that the experiments
were conducted at 298 K, so we can use Figures 1 and 2. Since we need to compare the N 2
values from Figures 1 and 2, it’s best to find values as exact as possible. Notice that at mass
6 g, the 2 L vessel has a pressure of 2,000 mmHg, and the 4 L vessel has a pressure of 1,000
mmHg. Therefore, the pressure in the 4 L vessel is half as great as the pressure in the 2 L
vessel. Only (A) works.
34 . G Use POE. In Figures 1 and 2, the pressure when N 2 is used is consistently greater than the
pressure when the NO 2 is used. Eliminate (H) and (J). Then you’ll need a bit of outside
knowledge to complete the question. Simply stated, an N 2 molecule has fewer components
than an NO 2 molecule, so it has a smaller mass. Therefore, in order to get the same mass of
both molecules, we will need more N 2 molecules per gram, eliminating (F).
35 . C This question requires a bit of outside knowledge. You need to know the relationship
between pressure and temperature: As pressure increases, so does temperature. This is a
direct relationship, eliminating (B) and (D). Because of this relationship, as the temperature
decreases from 298 K to 287 K, the pressure will decrease also, as in (C).
Passage VII
36 . J The first line of the passage states the following: The absolute threshold pressure for
hearing is the minimum air pressure at each audio frequency that can produce a sound
that is detectable by the human ear. In other words, the absolute threshold pressure for
hearing gives the highest pressure and frequency at which humans can hear. In order to
answer this question, we’ll need to use Figure 1 and the curve labeled “Absolute pressure
threshold for hearing,” and we will need to find its maximum frequency, listed on the x-axis.
According to Figure 1, this curve maxes out right around 1 × 10^3 cyc/sec, or 1,000 cyc/sec,
as in (J). If you selected (H) be careful, this is the point of minimum sound pressure level, not
the maximum frequency.
37 . D Use POE. Note the key at the bottom of Figure 1. According to this key, Water is shown on
the graph with a solid line, and Air is shown on the graph with a dotted line. The solid line is
