Passage VI

Three experiments were done using CO2, krypton(Kr), or O2. For each gas:

1. A 3 L steel vessel was fitted with a cap that contained agas inlet valve and a pressure and temperature sensor.

2. Air was pumped out of the vessel until the pressuremeasured 0.00 torr.

3. The vessel was placed on a balance, and the balance wasreset to 0.000 g.

4. Some of the gas was added to the vessel.

5. When the gas in the vessel reached room temperature(22°C), mass and pressure were recorded.

6. Steps 4 and 5 were repeated several times.

The experiments were then repeated, except that a 6 Lvessel was used (see Figures 1 and 2).

32. Suppose the experiments had been repeated, except with a 5 L vessel. Based on Figures 1 and 2, the pressure exerted by 7 g of CO2 would most likely have been:

Answer and Explanation

Your Answer is

Correct Answer is G

Explanation

The gas pressure formula in a closed container is P=nRT/V, where n is the number of molecules, R is a constant, T is the temperature, and V is the volume of the container.

So the bigger V is, the smaller P is. According to figure 2, when the volume is 6 L and the abscissa is 7, the ordinate corresponding to O2 is about 650. So when the volume is reduced to 5 L, the pressure should increase, but not so much above 1000