When 1.560 g of liquid hexane (C6H14) undergoes combustion in a bomb calorimeter, the temperature rises from 25.76 ∘C to 38.31 ∘C. Find ΔErxn for the reaction in kJ/mol hexane. The heat capacity of the bomb calorimeter, determined in a separate experiment, is 5.80 kJ/∘C.

Answer 1

How many mols is 1.560 g hexane? That's 1.560/about 86 = approx 0.02 mols but that's just an estimate.
The liquid hexane gave off q heat. How much? That's Ccal = 5.80 kJ/C x (dT) = estd 70 kJ
So heat combustion = approx 70 kJ/0.02 mols = about 3500 kJ/mol
Post your work if you get stuck.