Calculate the change of entropy, `Delta_(r)S^(Theta)` at `298K` for the reaction in which urea is formed from `NH_(3)` and `CO_(2)`.
`2NH_(3)(g)+CO_(2)(g) rarr NH_(2)CONH_(2)(aq)+H_(2)O(l)`
The standard entropies `(J K^(-1)mol^(-1))` are:
`NH_(2)CONH_(2)(aq) =174.0, H_(2)O(l) = 69.9`
`NH_(3)(g) = 192.3, CO_(2)(g) = 213.7`

Explanation

For the given change
`Delta_(r)S^(@)=Sigma n_(p)S_(p)^(@)-Sigma n_(R)S_(R)^(@)`
`=S_(NHCONH_(2))^(@)+S_(H_(2)O)^(@)-[2xxS_(NH_(3))^(@)+S_(CO_(2))^(@)]`
`=174.0+69.9-[2xx192.3+213.7]`
`=-354.4JK^(-1)mol^(-1)`