Question

1. a gas occupies 5.0 l at 27°c. what is the volume at 127°c, if pressure is constant?

a. 6.0 l
b. 5.5 l
c. 7.0 l
d. 10.0 l

1. a gas is at 2.5 atm and 300 k. if the temperature increases to 600 k, what is the new pressure (volume constant)?

a. 1.25 atm
b. 2.5 atm
c. 5.0 atm
d. 4.0 atm

Explanation:

Step1: Convert Celsius to Kelvin for problem 12

$T_1 = 27 + 273=300\ K$, $T_2=127 + 273 = 400\ K$, $V_1 = 5.0\ L$. According to Charles's law $\frac{V_1}{T_1}=\frac{V_2}{T_2}$.

Step2: Solve for $V_2$ in problem 12

$V_2=\frac{V_1T_2}{T_1}=\frac{5.0\times400}{300}=\frac{20}{3}\approx 6.0\ L$

Step3: Apply Gay - Lussac's law for problem 13

$P_1 = 2.5\ atm$, $T_1 = 300\ K$, $T_2 = 600\ K$. According to Gay - Lussac's law $\frac{P_1}{T_1}=\frac{P_2}{T_2}$.

Step4: Solve for $P_2$ in problem 13

$P_2=\frac{P_1T_2}{T_1}=\frac{2.5\times600}{300}=5.0\ atm$

Answer:

1. A. 6.0 L
2. C. 5.0 atm