Question

When a supply of hydrogen gas is held in a 4 liter container at 320 K it exerts a pressure of 800 torr. The supply is moved to a 2 liter container, and cooled to 160 K. What is the new pressure of the confined gas?

Answer 1

The answer is `P_2 = 800` `t o rr`.

The best way to approach this problem is by using the ideal gas law, `PV = nRT`. Since the hydrogen is moved from a container to another, we presume that the number of moles remains constant. This will give us 2 equations

`P_1V_1 = nRT_1` and `P_2V_2 = nRT_2`. Since `R` is a constant as well, we can write

`nR = (P_1V_1)/T_1 = (P_2V_2)/T_2 ->` the combined gas law.

Therefore, we have

`P_2 = V_1/V_2 * T_2/T_1 * P_1 = (4L)/(2L) * (160K)/(320K) * 800t o rr = 800t o rr`.