The combustion of 5.00 grams of c2h6 (g), at constant pressure releases 259 kj of heat. what is δh for the reaction: 2c2h6 (g) + 7o2 (g) = > 4co2 (g) + 6h2o (l) ?

The molar mass of C2H6 is 28 g/mol, so the number of moles is:

moles C2H6 = 5 / 28 = 0.179 mol

From the equation, there are 2 moles of C2H6, therefore the heat of reaction is:

δh = (259 kj / 0.179 mol) * 2 mol

δh = 2900 kJ = 2.9 MJ