At 82K, a gas has a volume of 4.60L. What would be the volume of the gas at 70K?

V₂ = 4.0L

Explanation:

Decreasing temperature = > Decreasing Volume (Charles Law)

For a given volume, use a temperature ratio that will give a smaller volume.

Volume at lower temp = 4.6L (70K/82K) = 4.0L ... Using (82K/70K) would give a larger volume = > contrary to temperature effects on gas volumes when pressure and mass are kept constant.

Pressure effects on Gas Volumes:

Note: The same idea is applied to pressure effects on gas volumes also except that changes in pressure affect gas volumes indirectly. That is, an increase in pressure = > decrease in volume, or a decrease in pressure = > increase in volume. Boyles Law = > V ∝ 1/P.

Given a gas volume of 4.60L at 760mmHg, what is volume at 848mmHg?

Increasing pressure = > Decreases Volume (Boyles Law)

For the given volume use a pressure ratio that will give a smaller volume.

Volume at higher pressure = 4.6L (760mm/848mm) = 4.1L. Using (848mm/760mm) would give a larger volume = > contrary to pressure effects on gas volume when temperature and mass of gas are kept constant.