What determines the direction of a reaction under standard state conditions?

[daphnelee-mh]

Homework Statement

If reactants and products were mixed in their standard-state concentrations,which direction would the reaction proceed?

Relevant Equations

Δ G = Δ H − T Δ S
Δ G = -RT ln K

For (1), I got the correct answer which is 28.76kj/mol.
For (2), the answer given is since Δ G > 0, the reaction proceed to left. I understand the meaning but what means by ' If reactants and products were mixed in their standard-state concentrations', is it indicate it is under standard state therefore just using the Δ G (standard) to determine the direction? As my first thought relates to the increasing in volume or concentration.

 

[mjc123]

You can do it two ways; standard state here means concentration = 1M, so if you plug this value into al the concentrations in the expression for Q, the reaction quotient, you will find that Q >> K, so reaction has to proceed to the left to reduce product concentrations and increase reagent concentrations until Q = K. Alternatively, if you have already calculated ΔG°, which you have, observing that ΔG° is positive means that the reverse reaction is spontaneous when everything is in the standard state.
(Note: be careful to distinguish between ΔG and ΔG°; you need to do this for part 3.)