Notifications
Clear all
0
06/10/2020 4:38 pm
Topic starter
Enthalpy of combustion of CH4, C2H6 and C3H8 are -210.8, -368.4 and -526.2 k cal mol-1 respectively. Enthalpy of combustion of hexane can be predicted as
(a) -840 k cal mol-1
(b) -684 k cal mol-1
(c) -1000 k cal mol-1
(d) none of these
1 Answer
0
06/10/2020 4:45 pm
(a) -840 k cal mol-1
Explanation:
ΔHc (C2H6) - ΔHc(CH4)
= -368.2 - (-210.8) = -157.4
ΔHc (C3H8) - ΔHc (C2H6)
= -526.2 - (-368.4) = -157.8
= -157.6 k cal mol-1
Then,
ΔHc (C6H14) = ΔHc (C3H8) + 3ΔHc (-CH2)
= -526.2 + 3(-157.6) = -999 k cal mol-1