ThermochemistryHard

Question

Consider the following data:

$\Delta_{f}H^{\Theta}($ methane, g$) = - XkJ{mol}^{- 1}$

Enthalpy of sublimation of graphite $= YkJ{mol}^{- 1}$

Dissociation enthalpy of $H_{2} = ZkJ{mol}^{- 1}$

The bond enthalpy of $C - H$ bond is given by:

Options

A.$\frac{X + Y + 2Z}{4}$
B.$\frac{X + Y + 4Z}{2}$
C.$X + Y + Z$
D.$\frac{- X + Y + Z}{4}$

Solution

$C(s) + 2H_{2}(\text{ }g) \rightarrow {CH}_{4}(\text{ }g)$

$- x = \left( \Delta H_{\text{sub~}} \right.\ $ of carbon $) + 2 \times ($ B.E. of $H - H)$

$- 4 \times ($ B.E. of $C - H)$

$- x = y + 2z - 4($ B.E. of $C - H)$

B.E. of $C - H = \frac{y + 2z + x}{4}$.

Create a free account to view solution

View Solution Free
Topic: Thermochemistry·Practice all Thermochemistry questions

More Thermochemistry Questions

What will be the heat of formation of methane, if the heat of combustion of carbon is′-x′ kJ, heat of format...For the given reactionsSiO2 + 4HF → SiF4 + 2H2O, ᐃH = -10.17 kcalSiO2 + 4HCl → SiCl4 + 2H2O, ᐃH ...The standard enthalpies of formation of NH3(g), CuO(s) and H2O(l) are −46, −155 and −285 kJ/mol, respectively. The entha...NH3(g) + 3Cl2(g) → NCl3(g) + 3HCl(g) ; ᐃH1N2(g) + 3H2(g) → 2NH3(g) ; ᐃH2H2(g) + Cl2(g) → 2...Oxidising power of chlorine in aqueous solution can be determined by the parameters indicated below: The energy involved...