Molar Gibbs Energy: 25{\circ} C Expansion Calculation

[patrickmoloney]

Homework Statement

Calculate the change in the molar Gibbs energy of a perfect gas when it expands isothermally and reversibly at a temperature of 25{\circ} Cfrom a molar volume of 4 \, \text{dm}^3 to a molar volume of 9 \, \text{dm}^3

Homework Equations

I derived the following equation

\Delta G = RT \ln \Big{(}\dfrac{V_i}{V_f}\Big{)}

The Attempt at a Solution

\Delta G = (8.314)(298.15)\ln \Big{(}\dfrac{4}{9}\Big{)}=-2010.15 \, \text{kJ/mol}

But apparently this is incorrect, I don't see what I did wrong. I'm fairly certain my derivation is correct.

Edit: \Delta G = -2.01 \, \text{kJ/mol}

 

[patrickmoloney]

Sorry the answer is not incorrect, it's simply units. I read the answer has to be in \text{KJ}\cdot \text{mol}^{-1}