Two equal masses of water, each of 1.0kg, are placed in a perfectly insulated container and allowed to mix without mechanical work. The initial temperatures of the samples are 353K and 293K respectively. Take the specific heat capacity of water as 4.2kJkg−1K−1 and treat it as constant over the temperature range involved.
(i) Determine the final equilibrium temperature of the mixture.
(ii) Calculate the entropy change of each water sample during the mixing.
(iii) Hence evaluate the total entropy change of the universe and state whether the mixing process is reversible or irreversible.