How do I solve this problem on a reaction between a NH3 and HCl?

Question

When 0.157 lol NH3 is reacted with excess HCl, 6.91 kJ of energy is released as heat. How do I calculate the energy change per mole of NH3?

Answer 1

I see you are listing a series of questions, so instead of doing them all for you, I'll guide you. Hope that's ok.

 

NH₃ + HCl ==>NH₄Cl 

If 0.157 moles of NH3 releases 6.91 kJ of energy, how much do you think will be releases by ONE mole?