How would increase in pressure and decrease in temperature of a gas affect the strength of force of attraction between the particles?

Answer 1

Using the Ideal Gas Law, PV = nRT, where P is the absolute pressure, V is the volume of gas, n is the number of moles, R is the gas constant and T is the temperature in degrees Kelvin, we can see how the attraction between the particles changes by inspecting the volume. The larger the volume of gas, the lesser force of attraction.

Typically, a decrease in temperature results in a smaller volume and the attractive forces between molecules are bigger. An increase in pressure also results in a smaller volume and again, the forces of attraction are made stronger, so the short answer would be that the forces of attraction are increased!

A more elaborate explanation follows:

1) V = nRT/P

Conditions:

R is a constant value, n is a constant value, T decreases, P increases.

Basically, we have gone from a scenario where everything is constant (state one) to the current state, where the conditions are as above. The changes this implement onto our system are easily distinguishable by comparing the first and second scenario.

Scenario one: V = nRT/P.

Scenario two: V = nR x (a smaller value)/bigger value → V = smaller value/bigger value → V = smaller.

The answer is that the volume will decrease, which means that the force of attraction is stronger.