Question

Ethanol (c2h5oh) burns according to the equation c2h5oh(l) + 3o2(g) â 2co2(g) + 3h2o(l), δh= -1367 kj/mol. how much heat is released when 35.0 g of ethanol is burned?

Answer 1

Molar mass of ethanol is: 46 grams/moles
C2H6O-> 2x12 + 6x1+ 16x1      (see periodic table)

If 46 g correspond to 1 mol, how much moles correspond 35 g?
46g ====1mol
35g====x
x= 35/46
x=0,76 mol

-1367 kj/mol, means that there are -1367 kj in one mol
1mol     ==== -1367 kj
0,76mol====  x
x=- 1040Kj


Ethanol released 1040 Kj.