Question

2NH4Cl(s)+Ba(OH)2⋅8H2O(s)→2NH3(aq)+BaCl2(aq)+10H2O(l) The ΔH for this reaction is 54.8kJ . How much energy would be absorbed if 27.7g of NH4Cl reacts?

Answer 1

the \(\Delta H\) is a stoichiometric quantity, just like the coefficients of the balanced reaction. Using 2 moles of \(NH_4Cl\) requires 54.8kJ of energy. That's what the balanced reaction says.

Convert your 27.7g of \(NH_4Cl\) into moles, then apply the stoichiometric ratio