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).

33. Based on Figures 1 and 2, for a given mass of O2 at 22°C, how does the pressure exerted by the O2 in a 6 L vessel compare to the pressure exerted by the O2 in a 3 L vessel? In the 6 L vessel, the O2 pressure will be:

Answer and Explanation

Your Answer is

Correct Answer is A

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. So the bigger V is, the smaller P is. It can be calculated by the formula that when V=6, the pressure is half of that when V=3