A certain mass of a gas occupies volume of 250 mL at 2 atm. Calculate the volume of gas if pressure is increased to 2.5 atm at constant temperature.

Vapour pressure of solution and of pure solvent are $$\mathrm{P}_1$$ and $$\mathrm{P}_1{ }^0$$ respectively. If $$\frac{P_1}{P_1^0}$$ is 0.15, find the mole fraction of solute.

Which of the following pairs of compounds is isomorphous?

What is internal energy change when $$62 \mathrm{~J}$$ of work is done on the system and $$128 \mathrm{~J}$$ of heat is transferred to surrounding?