What does `DeltaH` signify in each of the following equations?
(i) `HCl(g)+5H_(2)O(l)toHC l(5H_(2)O),DeltaH=-64kJ`
(ii) `HCl (g)+aqtoHC l(aq),DeltaH=-75kJ`
(iii) `HC l(5H_(2)O)+20H_(2)O(l)toHCl (25H_(2)O),DeltaH=-8.1kJ`.

Complete the following equations: O_(3)(g)+I^(-)(aq)+H_(2)O(l)to

Calculate the enthalpy of formation of liquid ethyl alcohol from the following data. C_(2)H_(5)OH(l)+3O_(2)(g)to2CO_(2)(g)+3H_(2)O(l),DeltaH=-1368kJ C(s)+O_(2)(g)toCO_(2)(g),DeltaH=-393kJ H_(2)(g)+(1)/(2)O_(2)(g)toH_(2)O(l),DeltaH=-287kJ .

Why are the standard reaction enthalpies of the following two reactions different? (1) C(graphite, s) +O_(2)(g)toCO_(2)(g),DeltaH^(0)=-393.5kJ (2) C(diamond, s) +O_(2)(g)toCO_(2)(g),DeltaH^(0)=-395.4kJ

Why is DeltaH=DeltaU for the following two reactions? Explain. (i) NaOH(aq)+HCl (aq)toNaCl(aq)+H_(2)O(l) (ii) CH_(4)(g)+2O_(2)(g) to CO_(2)(g)+2H_(2)O(g) .

Calculate the bond energy of O-H bond in H_(2)O(g) at the standard state from the following data: (1) H_(2)(g) to 2H(g),DeltaH^(0)=436kJ*mol^(-1) (2) (1)/(2)O_(2)(g)toO(g),DeltaH^(0)=249k*mol^(-1) (3) H_(2)(g)+(1)/(2)O_(2)(g)toH_(2)O(g),DeltaH_(f)^(0)[H_(2)O(g)]=-241.8kJ*mol^(-1) .

Calculate the standard enthalpy of formation of CH_(3)OH(l) from the following data: (1) CH_(3)OH(l)+(3)/(2)O_(2)(g)toCO_(2)(g)+2H_(2)O(l),Delta_(r)H^(0)=-726kJ*mol^(-1) (2) C(s)+O_(2)(g) to CO_(2)(g),Delta_(c)H^(0)=-393kJ*mol^(-1) (3) H_(2)(g)+(1)/(2)O_(2)(g)toH_(2)O(l),Delta_(f)H^(0)=-286kJ*mol^(-1) .

Diborane [B_(2)H_(6)(g)] is used as a very effective fuel for rockets. Calculate the heat of combustion of diborane for the following reaction: B_(2)H_(6)(g)+3O_(2)(g)toB_(2)O_(3)(g)+3H_(2)O(g) Given: (1) 2B(s)+(3)/(2)O_(2)(g)toB_(2)O_(3) (s),DeltaH^(0)=-1273kJ*mol^(-1) (2) H_(2)(g)+(1)/(2)O_(2)(g)toH_(2)O(l),DeltaH^(0)=-285.8kJ*mol^(-1) . (3) H_(2)O(l)toH_(2)O(g),DeltaH^(0)=+44kJ*mol^(-1) (4) 2B(s)+3H_(2)(g) to B_(2)H_(6)(g),DeltaH^(0)=+36kJ*mol^(-1) .

DeltaH value for the given reactions at 25^(@)C are- C_(3)H_(8)(g)to3C(s)+4H_(2)(g),DeltaH^(0)=103.8kJ*mol^(-1) 2H_(2)(g)+O_(2)(g) to 2H_(2)O(l),DeltaH^(0)=-571.6kJ*mol^(-1) C_(2)H_(6)(g)+(7)/(2)O_(2)(g)to2CO_(2)(g)+3H_(2)O(l),DeltaH^(0)=-1560kJ*mol^(-1) CH_(4)(g)+2O_(2)(g) to CO_(2)(g)+2H_(2)O(l),DeltaH^(0)=-890kJ*mol^(-1) C(s)+O_(2)(g) to CO_(2)(g),DeltaH^(0)=-393.5kJ*mol^(-1) Calculate DeltaH^(0) for the reaction at 25^(@)C C_(3)H_(8)(g)+H_(2)(g)toC_(2)H_(6)(g)+CH_(4)(g)

H_(2)(g)+(1)/(2)O_(2)(g)toH_(2)O(l),DeltaH=-285.8kJ . What will be the value of DeltaH for the reaction: 2H_(2)O(l)to2H_(2)(g) +O_(2)(g) ?