Question

A 7.0 L sample of gas begins at 2.5 atm and 320. K. What is the new pressure if the temperature is changed to 273 K and the volume remains constant at 7.0 L?

Answer 1

Answer:

2.1 atm

Explanation:

We are given the following variables to work with:

Initial pressure (P1): 2.5 atm

Initial temperature (T1): 320 K

Final temperature (T2): 273 K

Constant volume: 7.0 L

We are asked to find the final pressure (P2). Since volume is constant, we want to choose a gas law equation that relates initial pressure and temperature to final pressure and temperature. Gay-Lussac's law does this:

$\frac{P_{1}}{T_1} =\frac{P_{2}}{T_2}$

We can rearrange the law algebraically to solve for $P_{2}$.

${P_{2}} =\frac{(T_2)(P_{1} )}{T_1}$

Substitute your known variables and solve:

$P_2 = \frac{273K(2.5atm)}{320K} = 2.1 atm$