[peach_hime]

When calculating entropy changes, why don't we convert our values for making one mole? How do I know whether to balance the equation using whole numbers, or can I use fractions?

e.g. Calculate the change in entropy associated with the Haber process for the production of ammonia from nitrogen and hydrogen gas.
At 298K as a standard temperature:
S(NH3) = 192.5 J/mol K
S(H2) = 130.6 J/mol K
S(N2) = 191.5 J/mol K
The correct answer is -198.3 J/K/mol

Why can I not balance the equation to make one mole of ammonia using fractions? I would get -99.5 J/K/mol though and this is not the correct entropy change.

[BlitzHypercharge]

You would have to keep the stoichiometric coefficient of nh3 as 1