Here is a thermochmistry q.?

Question

A sample of a hydrocarbon is combusted completely in oxygen gas to produce 21.83g of carbondioxide, 4.47g of water(in gaseous form) and 311kJ of heat. (a) what is the mass of the hydrocarbon sample that was combusted? (b)what is the empirical formula of the hydrocarbon? (c) whats the value of delta H per empirical formula unit of the hydrocarbon?

Answer 1

21.83g of carbondioxide <==> 21.83g *(12.01/44.01) = 5.957g carbon
4.47g of water <==> 4.47g *(2.02/18.02) = 0.501g H

(a) the mass of the hydrocarbon sample that was combusted:
5.957g + 0.501g = 6.458g
(b) 21.83/44.01 = 0.4960 mol
4.47*2/18.02 = 0.496 mol
the empirical formula of the hydrocarbon is: CH
(c) 311kJ/0.496 mol = 627kJ/mol