Passage VI

Figure 1 shows how the H2O vapor pressure (the pressure exerted by the H2O vapor in air) varies with the rela­tive humidity (RH) of the air at CTP, which denotes a constant temperature of 25°C and pressure of 101,325 pas­cal (Pa). Figure 2 shows how air density varies with H2O vapor pressure at CTP.

At CTP, the air above an aqueous solution in a closed container has a constant RH. Figure 3 shows, for 3 com­pound, how the RH of the air at CTP in a closed container varies with the percent by mass, of the compound dissolved in the aqueous solution in the container.

Figure 3 adapted from James G Speight, Labge's Handbook of Chemistry, 16th ed. ©2005 by McGraw-Hill, Inc.

36. Based on Figure 2, air at CTP that has a density of 1,172 g/m3 will have an H2O vapor pressure closest to which of the following?

Answer and Explanation

Your Answer is

Correct Answer is G

Explanation

When the air density decreases by 2g/m³, the water vapor pressure increases by about 400Pa. When the air density is 1174g/m³, the water vapor pressure is about 2300pa; when the air density is 1172g/m³, the water vapor pressure should be about 2700pa.