How much potassium nitrate has to dissolve in water to absorb 120 kj of heat?

From the sources, it may be found that the heat of solution of potassium nitrate (KNO3) is equal to 34.89 kJ/mol. In order to absorb 120 kJ of heat, the amount of potassium nitrate that should be added to water to form the solution is,
                               120 kJ = (34.89 kJ/mol)(x)
The value of x is approximately equal to 3.44 mols. This is equal to 347.72 grams of potassium nitrate. 

They are all full and don't need any more electrons in there outer shell.