Science Homework Help

I am working through an experiment where 3.016g of NH4NO3(s) was dissolved in 50g of H2O in a coffee cup calorimeter. I determined the qrxn = 19.655 kJ/mol (qsoln + qcup). I am now asked to calculate the change in enthalpy for the reaction in moles using deltaHrxn = Sigma deltaHf(products) – Sigma deltaHf(reactants) and the deltaHf NH4NO3 is -495 kJ/mol. I am stuck here, blanking out on how to proceed