Question

a sample of gas goes from an unknown pressure at 315 k to 2.64 atm at 475 k. what is the initial pressure of the gas?
p = ? atm

Explanation:

Step1: Use Gay-Lussac's Law

$\frac{P_1}{T_1} = \frac{P_2}{T_2}$ where $P_1$=initial pressure, $T_1=315$ K, $P_2=2.64$ atm, $T_2=475$ K.

Step2: Rearrange for $P_1$

$P_1 = P_2 \times \frac{T_1}{T_2}$

Step3: Calculate $P_1$

$P_1 = 2.64 \times \frac{315}{475} \approx 1.75$ atm

Answer:

1.75