Question

Calculate ?Hrxn for the following reaction:
CH4(g)+4Cl2(g)?CCl4(g)+4HCl(g)
Use the following reactions and given ?H?s.
C(s)+2H2(g)?CH4(g)?H=?74.6kJC(s)+2Cl2(g)?CCl4(g)?H=?95.7kJH2(g)+Cl2(g)?2HCl(g)?H=?184.6kJ

Express your answer using one decimal place.

?Hrxn =___________kJ

Answer 1

C(s) + 2H2(g) ------> CH4 delta H = -74.6KJ

CH4-----> C(S) + 2H2 (g) delta H = +74.6 KJ .......1

C(s) + 2Cl2 (g) ------> CCl4 delta H = - 95.7KJ ......2

H2(g) + Cl2 (g) ------> 2HCl(g)   delta H = -184.6KJ ......x2

2H2(g)+2Cl2(g) --------> 4HCl(g)        delta H = - 369.2KJ ........3

adding equation 1,2 & 3

CH4(g) + 4Cl2(g)-------> CCl4(g) + 4HCl(g)

delta H= 74.6 - 95.7KJ - 369.2 KJ = - 390.3KJ