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 $25{\circ} C$from 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 $\text{KJ}\cdot \text{mol}^{-1}$