calculate the amount of heat required to decompose 8 mol of NaHCO3(s)

Question

2NaHCO3(s) + 94000 J = Na2CO3(s)+ H2O(g) + CO2(g)

Answer 1

Look up the delta H formation for the materials in your text/notes. Then
dH rxn = (n*dHo formation products) - (n*dHo formation reactants)