**18.7** A nonideal gas is initially at equilibrium when it is suddenly and rapidly compressed isothermally to ten times its original pressure. The system then returns to equilibrium. Indicate whether each of the following increases, decreases, or stays the same, or there is not enough information to tell.(a) The average kinetic energy.(b) The average potential energy.(c) The Gibbs free energy.

Isothermal conditions of a system in which temperature is maintained constant. Isothermal compression means that no temperature is required to add or remove heat from the system. Pressure is increased in isothermal compression. Non-ideal gas follows Vander Waals forces.In Non-Ideal gas, initially at equilibrium and compressed rapidly where pressure is increased at isothermal conditions. Average kinetic energy is directly proportional to temperature. Isothermal conditions mean that the temperature in the system is constant. So, the average kinetic energy is constant in the system. Average potential energy is defined by the intermolecular forces between molecules of the system. As the pressure is directly proportional to intermolecular forces. The pressure increases, then intermolecular forces also increase, which increases average potential energy. Gibbs's free energy in the isothermal process is dependent on pressure and volume. As pressure increases with isothermal conditions, Gibb's free energy will also increase. Final answer a) Average kinetic energy increase b) Average potential energy increase c) Gibbs free energy also increases