Calculate the heat change for the reaction, c+2s gives cs2 from the following equations c +o2 gives co2 delta h =-393.5kj per mole. C+o2 gives so2 delta h =-293.7kj per mole and cs2+3o2gives co2 +2so2 delta h =-110kj per mole calculate by the hess's law

Dear student,

The given equations are :
  C  + O₂ $\stackrel{}{\to }$ CO₂      △ H = -393.5 kJ / mol  .........(I)
 S  +  O₂  $\stackrel{}{\to }$ SO₂     △ H =  - 293.7 KJ/mol  ........(II)
CS₂ + 3 O₂ $\stackrel{}{\to }$ CO₂  + 2SO₂  △ H =  - 110 KJ/mol  ........(III)
Required equation is ;  C  + 2 S $\stackrel{}{\to }$ CS₂   △ H =  ?
  On adding the eq. (i)  + 2 x eq. (ii) ;  C + 2 S + 3 O₂ $\stackrel{}{\to }$ CO₂  + 2 SO₂ .......(iv)     △ H =  - 393.5  + 2 x ( - 293.7)  = - 980.9 kj /mol
again eq. (iv) - eq. (iii) 
 C + 2 S $\stackrel{}{\to }$ CS₂   △ H =  - 980.9 - ( - 110) =  - 870.9 KJ / mol
  Regards