Define system and surrounding.

System performed pressure volume work when in between system and surrounding there is

If the change in entropy of reversible isothermal expansion of 1 mol of an ideal gas is 9.135 " J mol"^(-1). K^(-1) , what will be the entropy change of the surroundings and universe ? If the above expansion of gas is allowed to occur against zero pressure, what will be the entropy change of the system and surroundings ?

In a reversible process, if changes in entropy of the system and its surroundings are DeltaS_(1) & DeltaS_(2) respectively, then-

In a process, the value of the change in entropy of the system and its surroundings are x and -y J*K^(-1) . If xgty, then will the process be spontaneous?

A system undergoes a process in which it gives up 900 J of heat and its internal energy decreases by 300 J. of the system and its surroundings, which one does work in this process?

Heat is not exchange between the system and its surroundings during free expansion of an ideal gas. Therefore, in this process, q=0. will the change in entropy in this process be zero?

Among pressure of the system and the surroundings, which one is represented by 'P' in the equation H=U+PV ? What would be the change in enthalpy for the reaction A_(2)(s)+B_(2)(g) to 2AB(g) ?

There occurs no exchange of heat between a system and its surroundings in an adiabatic process. So, the change in entropy of the system is zero in this process. Justify the statement.

A process occurring in an isolated system does not have any effect on its surrounding and the process is also not influenced by its surroundings. Why?