The gas laws describe the behavior of gases under specific conditions of temperature, pressure, and volume. Three gas laws show the relationship between two variables when all others are held constant: Boyle’s law (pressure and volume are inversely proportional), Charles’s law (volume and temperature are directly proportional), and Gay-Lussac’s law (temperature and pressure are directly proportional).
The three laws can be combined into one law, called the combined gas law.
pressure times volume over temperature under conditions 1 equals pressure times volume over temperature under conditions 2
A sample of chlorine gas has a volume of 2.61 L, a pressure of 0.85 atm, and a temperature of 292 K. What is the new volume, if the new pressure is 0.65 atm and the new temperature is 298 K?
Using the combined gas law formula:
\(P_1V_1/T_1 = P_2V_2/T_2\)
Plug in the given values:
\(0.85 \, atm \times 2.61 \, L / 292 \, K = 0.65 \, atm \times V_2 / 298 \, K\)
\(V_2 = (0.85 \, atm \times 2.61 \, L \times 298 \, K ) / (0.65 \, atm \times 292 \, K)\)
\(V_2 ≈ 2.26 \, L\)
Therefore, the new volume of the chlorine gas is approximately 2.26 L.