Answer
The final pressure of the gas is equal to 3.07 atm.
Work Step by Step
1. The temperatures used in gas law calculations must be converted to Kelvin values.
$C^o + 273 = K$
$25 + 273 = K$
$K = 298$
Therefore: $T_1 = 298 \space K$
$C^o + 273 = K$
$12 + 273 = K$
$K = 285$
Therefore: $T_2 = 285 \space K$
2. Write the combined gas law, and rearrange it to solve for $P_2$, which is the final pressure.
$\frac{P_1V_1}{T_1} = \frac{P_2V_2}{T_2}$
- Divide both sides by $V_2$:
$\frac{P_1V_1}{T_1V_2} = \frac{P_2}{T_2}$
- Multiply both sides by $T_2$:
$\frac{P_1V_1T_2}{T_1V_2} = P_2$
3. Substitute the values and find the $P_2$ value:
$\frac{845 \space mmHg \times 6.50 \space L \times 285 \space K}{298 \space K \times 2.25 \space L } = P_2$
$P_2 = 2330 \space mmHg$
4. Convert the final pressure to atmospheres:
$2330 \space mmHg \times \frac{1 \space atm}{760 \space mmHg} = 3.07 \space atm$
$P_2 = 3.07 \space atm$
