Calculate the pressure of a helium sample at -207.3°C and 768 mL if it exerts a pressure of 175 kPa at 25.0°C and 925 mL.

Question

Quizplus · Accepted Answer

To solve this problem, we need to use the combined gas law, which states that PV/T is constant for a fixed amount of gas. We can set up the equation as follows:

(P1V1)/T1 = (P2V2)/T2

We are given P1, V1, and T1 (25.0°C = 298.2 K). We are looking for P2, given V2 (768 mL = 0.768 L) and T2 (-207.3°C = 65.9 K).

(P1V1)/T1 = (P2V2)/T2
(175 kPa)(925 mL) / (298.2 K) = (P2)(768 mL) / (65.9 K)

Simplifying this equation and solving for P2, we get:

P2 = (175 kPa)(925 mL)(65.9 K) / (298.2 K)(768 mL)
P2 = 46.6 kPa

Therefore, the answer is B.

Calculate the Pressure of a Helium Sample at -207