Concrete is produced form a mixture of cement, water and small stones. Small amount of gypsum, `CaSO_(4).2H_(2)O` is added in cement production to improve the subsequent hardening of concrete. The elevated temperature during the production of cement may lead to the formation of unwanted hemihydrate `CaSO_(4).(1)/(2)H_(2)O` according to reaction.
`CaSO_(4).2H_(2)O(s) rarr CaSO_(4).(1)/(2)H_(2)O(s)+(3)/(2)H_(2)O(g)`
The `Delta_(f)H^(Theta) of CaSO_(2).2H_(2)O(s),CaSO_(4)(1)/(2)H_(2)O(s),H_(2)O(g)`
are `-2021.0 kJ mol^(-1), -1575.0 kJ mol^(-1)` and `-241.8 kJ mol^(-1)`, respectively. The respective values of their standard entropies are `194.0, 130.0` and `188.0 J K^(-1)mol^(-1)`. The values of `R = 8.314JK^(-1)mol^(-1) = 0.0831L` bar `mol^(-1)K^(-1)`.
Answer the following questions on the basis of above information.
The value of `DeltaG^(Theta)` for the reaction at `298K` is

Answer

(i)-4.031 MeV, Endothermic
(ii)+4.616 MeV, Exothermic

Explanation

(i)Mass of LHS = 4.023874 u
Mass of RHS =4.028204 u
Q=[(Mass of LHS-Mass of RHS) u] x 931 MeV
Q=-4.031 MeV `rArr` reaction is endothermic
(ii)[12.000000+12.000000-(19.992439+4.002603)] x 931
Q=4.616 MeV
Q is positive `rArr` reaction is exothermic