Calculate the enthalpy of formation of Benzene represented by following reaction: 6C + 2H2 gives C6H6 The standard enthalpy of - Chemistry - Thermodynamics

Question

Calculate the enthalpy of formation of Benzene represented by
following reaction:
6C + 2H2 gives C6H6
The standard enthalpy of combustion of Benzene is -3266 0 kJ and
standard enthalpy of formation of CO2 and H2O are -393 1 kJ and
-286 0 kJ respectively

Vartika Jain · Accepted Answer

According to the given information
(i) C6H6 (l)+ 153O2 (g)→  6CO2(g) +  3H2O(l)                ∆H=-3266
0 kJ(ii) C(s) + O2 (g) → CO2 (g)                                                  ∆H=-393
1 kJ(iii) H2 (g)  + 12O2 (g)  →H2O(l)                                          ∆H= -286
0 kJThe required equation is:6C(s)  + 3H2(g) →C6H6(l)                                                    ∆H= ?
Method to solve the problem:
The heat required equation can be obtained by algebraic method

Multiply reaction (ii) by 6 and reaction (iii) by 3 and write (i)
in reverse form Add all the three equation

6C(s)+ 6O2(g) → 6CO2(g);                                    ∆H=-393
1×6 kJ=2358
6 kJ3H2(g) + 32O2(g) → 3H2O(l);                               ∆H=-286
0×3 kJ=858 kJ6CO2(g) + 3H2O(l)→ C6H6(l) + 152O2(g);        ∆H= + 3266
0 kJOn adding the three equations,6C(s) + 3H2(g) →  C6H6(l);                                     ∆H= + 3266
0 kJ-2358
6 kJ-858 kJ                                                                                       ∆H= + 49
4 kJ
Hence, the enthalapy of formation of benzene is 49 4
kJ

Calculate the enthalpy of formation of Benzene represented by following reaction: 6C + 2H2 gives C6H6 The standard enthalpy of combustion of Benzene is -3266.0 kJ and standard enthalpy of formation of CO2 and H2O are -393.1 kJ and -286.0 kJ respectively.

Calculate the enthalpy of formation of Benzene represented by following reaction:
6C + 2H2 gives C6H6
The standard enthalpy of combustion of Benzene is -3266.0 kJ and standard enthalpy of formation of CO2 and H2O are -393.1 kJ and -286.0 kJ respectively.