Heat of Reaction
CHXI06:THERMODYNAMICS

369538 If the bond energies of \(\mathrm{\mathrm{H}-\mathrm{H}, \mathrm{Br}-\mathrm{Br}}\) and \(\mathrm{\mathrm{H}-\mathrm{Br}}\) are 433, 192 and \(\mathrm{364 \mathrm{~kJ} \mathrm{~mol}^{-1}}\) respectively, then \(\mathrm{\Delta \mathrm{H}^{\circ}}\) for the reaction:
\(\mathrm{\mathrm{H}_{2(\mathrm{~g})}+\mathrm{Br}_{2(\mathrm{~g})} \rightarrow 2 \mathrm{HBr}_{(\mathrm{g})}}\) is

1 \(\mathrm{-261 \mathrm{~kJ}}\)
2 \(\mathrm{+103 \mathrm{~kJ}}\)
3 \(\mathrm{+261 \mathrm{~kJ}}\)
4 \(\mathrm{-103 \mathrm{~kJ}}\)
CHXI06:THERMODYNAMICS

369539 The enthalpy of atomisation for the reaction \(\mathrm{\mathrm{CH}_{4(\mathrm{~g})} \rightarrow \mathrm{C}_{(\mathrm{g})}+4 \mathrm{H}_{(\mathrm{g})}}\) is \(\mathrm{1665 \mathrm{~kJ} \mathrm{~mol}^{-1}}\). The bond energy of \(\mathrm{\mathrm{C}-\mathrm{H}}\) bond is

1 \(\mathrm{832.5 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
2 \(\mathrm{416.2 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
3 \(\mathrm{1665 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
4 \(\mathrm{208.1 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
CHXI06:THERMODYNAMICS

369540 The bond dissociation energies of \(\mathrm{X_{2}, Y_{2}}\) and \(\mathrm{X Y}\) are in the ratio of \(\mathrm{1: 0.5: 1 . \Delta H}\) for the formation of \(\mathrm{X Y}\) is \(\mathrm{-200 \mathrm{~kJ} \mathrm{~mol}^{-1}}\). The bond dissociation energy of \(\mathrm{X_{2}}\) will be

1 \(\mathrm{800 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
2 \(\mathrm{400 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
3 \(\mathrm{100 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
4 \(\mathrm{200 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
CHXI06:THERMODYNAMICS

369541 In the dissociation of \(\mathrm{\mathrm{CH}_{4}(\mathrm{~g})}\),

1 Bond energies of all the \(\mathrm{\mathrm{C}-\mathrm{H}}\) bonds are equal
2 No two bonds have equal energy
3 Two bonds have equal energy
4 Three bonds have equal energy
CHXI06:THERMODYNAMICS

369542 The enthalpy changes for the following processes are listed below
\({\rm{C}}{{\rm{l}}_{\rm{2}}}{\rm{(\;g)}} \to {\rm{2Cl(g),}}\quad {\rm{242}}{\rm{.3\;kJ\;mo}}{{\rm{l}}^{{\rm{ - 1}}}}\)
\({{\rm{I}}_{\rm{2}}}{\rm{(\;g)}} \to {\rm{2I(g),151}}{\rm{.0\;kJ\;mo}}{{\rm{l}}^{{\rm{ - 1}}}}\)
\({\rm{ICl(g)}} \to {\rm{I(g) + Cl(g),211}}{\rm{.3\;kJ\;mo}}{{\rm{l}}^{{\rm{ - 1}}}}\)
\({{\rm{I}}_{\rm{2}}}{\rm{(\;s)}} \to {{\rm{I}}_{\rm{2}}}{\rm{(\;g),}}\quad {\rm{62}}{\rm{.76\;kJ\;mo}}{{\rm{l}}^{{\rm{ - 1}}}}\)
Given that the standard states for iodine and chlorine are \(\mathrm{\mathrm{I}_{2}(\mathrm{~s})}\) and \(\mathrm{\mathrm{Cl}_{2}(\mathrm{~g})}\), the standard enthalpy of formation for \(\mathrm{\mathrm{ICl}(\mathrm{g})}\) is

1 \(\mathrm{-14.6 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
2 \(\mathrm{-16.8 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
3 \(\mathrm{+16.8 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
4 \(\mathrm{+244.8 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
CHXI06:THERMODYNAMICS

369538 If the bond energies of \(\mathrm{\mathrm{H}-\mathrm{H}, \mathrm{Br}-\mathrm{Br}}\) and \(\mathrm{\mathrm{H}-\mathrm{Br}}\) are 433, 192 and \(\mathrm{364 \mathrm{~kJ} \mathrm{~mol}^{-1}}\) respectively, then \(\mathrm{\Delta \mathrm{H}^{\circ}}\) for the reaction:
\(\mathrm{\mathrm{H}_{2(\mathrm{~g})}+\mathrm{Br}_{2(\mathrm{~g})} \rightarrow 2 \mathrm{HBr}_{(\mathrm{g})}}\) is

1 \(\mathrm{-261 \mathrm{~kJ}}\)
2 \(\mathrm{+103 \mathrm{~kJ}}\)
3 \(\mathrm{+261 \mathrm{~kJ}}\)
4 \(\mathrm{-103 \mathrm{~kJ}}\)
CHXI06:THERMODYNAMICS

369539 The enthalpy of atomisation for the reaction \(\mathrm{\mathrm{CH}_{4(\mathrm{~g})} \rightarrow \mathrm{C}_{(\mathrm{g})}+4 \mathrm{H}_{(\mathrm{g})}}\) is \(\mathrm{1665 \mathrm{~kJ} \mathrm{~mol}^{-1}}\). The bond energy of \(\mathrm{\mathrm{C}-\mathrm{H}}\) bond is

1 \(\mathrm{832.5 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
2 \(\mathrm{416.2 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
3 \(\mathrm{1665 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
4 \(\mathrm{208.1 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
CHXI06:THERMODYNAMICS

369540 The bond dissociation energies of \(\mathrm{X_{2}, Y_{2}}\) and \(\mathrm{X Y}\) are in the ratio of \(\mathrm{1: 0.5: 1 . \Delta H}\) for the formation of \(\mathrm{X Y}\) is \(\mathrm{-200 \mathrm{~kJ} \mathrm{~mol}^{-1}}\). The bond dissociation energy of \(\mathrm{X_{2}}\) will be

1 \(\mathrm{800 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
2 \(\mathrm{400 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
3 \(\mathrm{100 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
4 \(\mathrm{200 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
CHXI06:THERMODYNAMICS

369541 In the dissociation of \(\mathrm{\mathrm{CH}_{4}(\mathrm{~g})}\),

1 Bond energies of all the \(\mathrm{\mathrm{C}-\mathrm{H}}\) bonds are equal
2 No two bonds have equal energy
3 Two bonds have equal energy
4 Three bonds have equal energy
CHXI06:THERMODYNAMICS

369542 The enthalpy changes for the following processes are listed below
\({\rm{C}}{{\rm{l}}_{\rm{2}}}{\rm{(\;g)}} \to {\rm{2Cl(g),}}\quad {\rm{242}}{\rm{.3\;kJ\;mo}}{{\rm{l}}^{{\rm{ - 1}}}}\)
\({{\rm{I}}_{\rm{2}}}{\rm{(\;g)}} \to {\rm{2I(g),151}}{\rm{.0\;kJ\;mo}}{{\rm{l}}^{{\rm{ - 1}}}}\)
\({\rm{ICl(g)}} \to {\rm{I(g) + Cl(g),211}}{\rm{.3\;kJ\;mo}}{{\rm{l}}^{{\rm{ - 1}}}}\)
\({{\rm{I}}_{\rm{2}}}{\rm{(\;s)}} \to {{\rm{I}}_{\rm{2}}}{\rm{(\;g),}}\quad {\rm{62}}{\rm{.76\;kJ\;mo}}{{\rm{l}}^{{\rm{ - 1}}}}\)
Given that the standard states for iodine and chlorine are \(\mathrm{\mathrm{I}_{2}(\mathrm{~s})}\) and \(\mathrm{\mathrm{Cl}_{2}(\mathrm{~g})}\), the standard enthalpy of formation for \(\mathrm{\mathrm{ICl}(\mathrm{g})}\) is

1 \(\mathrm{-14.6 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
2 \(\mathrm{-16.8 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
3 \(\mathrm{+16.8 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
4 \(\mathrm{+244.8 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
CHXI06:THERMODYNAMICS

369538 If the bond energies of \(\mathrm{\mathrm{H}-\mathrm{H}, \mathrm{Br}-\mathrm{Br}}\) and \(\mathrm{\mathrm{H}-\mathrm{Br}}\) are 433, 192 and \(\mathrm{364 \mathrm{~kJ} \mathrm{~mol}^{-1}}\) respectively, then \(\mathrm{\Delta \mathrm{H}^{\circ}}\) for the reaction:
\(\mathrm{\mathrm{H}_{2(\mathrm{~g})}+\mathrm{Br}_{2(\mathrm{~g})} \rightarrow 2 \mathrm{HBr}_{(\mathrm{g})}}\) is

1 \(\mathrm{-261 \mathrm{~kJ}}\)
2 \(\mathrm{+103 \mathrm{~kJ}}\)
3 \(\mathrm{+261 \mathrm{~kJ}}\)
4 \(\mathrm{-103 \mathrm{~kJ}}\)
CHXI06:THERMODYNAMICS

369539 The enthalpy of atomisation for the reaction \(\mathrm{\mathrm{CH}_{4(\mathrm{~g})} \rightarrow \mathrm{C}_{(\mathrm{g})}+4 \mathrm{H}_{(\mathrm{g})}}\) is \(\mathrm{1665 \mathrm{~kJ} \mathrm{~mol}^{-1}}\). The bond energy of \(\mathrm{\mathrm{C}-\mathrm{H}}\) bond is

1 \(\mathrm{832.5 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
2 \(\mathrm{416.2 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
3 \(\mathrm{1665 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
4 \(\mathrm{208.1 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
CHXI06:THERMODYNAMICS

369540 The bond dissociation energies of \(\mathrm{X_{2}, Y_{2}}\) and \(\mathrm{X Y}\) are in the ratio of \(\mathrm{1: 0.5: 1 . \Delta H}\) for the formation of \(\mathrm{X Y}\) is \(\mathrm{-200 \mathrm{~kJ} \mathrm{~mol}^{-1}}\). The bond dissociation energy of \(\mathrm{X_{2}}\) will be

1 \(\mathrm{800 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
2 \(\mathrm{400 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
3 \(\mathrm{100 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
4 \(\mathrm{200 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
CHXI06:THERMODYNAMICS

369541 In the dissociation of \(\mathrm{\mathrm{CH}_{4}(\mathrm{~g})}\),

1 Bond energies of all the \(\mathrm{\mathrm{C}-\mathrm{H}}\) bonds are equal
2 No two bonds have equal energy
3 Two bonds have equal energy
4 Three bonds have equal energy
CHXI06:THERMODYNAMICS

369542 The enthalpy changes for the following processes are listed below
\({\rm{C}}{{\rm{l}}_{\rm{2}}}{\rm{(\;g)}} \to {\rm{2Cl(g),}}\quad {\rm{242}}{\rm{.3\;kJ\;mo}}{{\rm{l}}^{{\rm{ - 1}}}}\)
\({{\rm{I}}_{\rm{2}}}{\rm{(\;g)}} \to {\rm{2I(g),151}}{\rm{.0\;kJ\;mo}}{{\rm{l}}^{{\rm{ - 1}}}}\)
\({\rm{ICl(g)}} \to {\rm{I(g) + Cl(g),211}}{\rm{.3\;kJ\;mo}}{{\rm{l}}^{{\rm{ - 1}}}}\)
\({{\rm{I}}_{\rm{2}}}{\rm{(\;s)}} \to {{\rm{I}}_{\rm{2}}}{\rm{(\;g),}}\quad {\rm{62}}{\rm{.76\;kJ\;mo}}{{\rm{l}}^{{\rm{ - 1}}}}\)
Given that the standard states for iodine and chlorine are \(\mathrm{\mathrm{I}_{2}(\mathrm{~s})}\) and \(\mathrm{\mathrm{Cl}_{2}(\mathrm{~g})}\), the standard enthalpy of formation for \(\mathrm{\mathrm{ICl}(\mathrm{g})}\) is

1 \(\mathrm{-14.6 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
2 \(\mathrm{-16.8 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
3 \(\mathrm{+16.8 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
4 \(\mathrm{+244.8 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
CHXI06:THERMODYNAMICS

369538 If the bond energies of \(\mathrm{\mathrm{H}-\mathrm{H}, \mathrm{Br}-\mathrm{Br}}\) and \(\mathrm{\mathrm{H}-\mathrm{Br}}\) are 433, 192 and \(\mathrm{364 \mathrm{~kJ} \mathrm{~mol}^{-1}}\) respectively, then \(\mathrm{\Delta \mathrm{H}^{\circ}}\) for the reaction:
\(\mathrm{\mathrm{H}_{2(\mathrm{~g})}+\mathrm{Br}_{2(\mathrm{~g})} \rightarrow 2 \mathrm{HBr}_{(\mathrm{g})}}\) is

1 \(\mathrm{-261 \mathrm{~kJ}}\)
2 \(\mathrm{+103 \mathrm{~kJ}}\)
3 \(\mathrm{+261 \mathrm{~kJ}}\)
4 \(\mathrm{-103 \mathrm{~kJ}}\)
CHXI06:THERMODYNAMICS

369539 The enthalpy of atomisation for the reaction \(\mathrm{\mathrm{CH}_{4(\mathrm{~g})} \rightarrow \mathrm{C}_{(\mathrm{g})}+4 \mathrm{H}_{(\mathrm{g})}}\) is \(\mathrm{1665 \mathrm{~kJ} \mathrm{~mol}^{-1}}\). The bond energy of \(\mathrm{\mathrm{C}-\mathrm{H}}\) bond is

1 \(\mathrm{832.5 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
2 \(\mathrm{416.2 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
3 \(\mathrm{1665 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
4 \(\mathrm{208.1 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
CHXI06:THERMODYNAMICS

369540 The bond dissociation energies of \(\mathrm{X_{2}, Y_{2}}\) and \(\mathrm{X Y}\) are in the ratio of \(\mathrm{1: 0.5: 1 . \Delta H}\) for the formation of \(\mathrm{X Y}\) is \(\mathrm{-200 \mathrm{~kJ} \mathrm{~mol}^{-1}}\). The bond dissociation energy of \(\mathrm{X_{2}}\) will be

1 \(\mathrm{800 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
2 \(\mathrm{400 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
3 \(\mathrm{100 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
4 \(\mathrm{200 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
CHXI06:THERMODYNAMICS

369541 In the dissociation of \(\mathrm{\mathrm{CH}_{4}(\mathrm{~g})}\),

1 Bond energies of all the \(\mathrm{\mathrm{C}-\mathrm{H}}\) bonds are equal
2 No two bonds have equal energy
3 Two bonds have equal energy
4 Three bonds have equal energy
CHXI06:THERMODYNAMICS

369542 The enthalpy changes for the following processes are listed below
\({\rm{C}}{{\rm{l}}_{\rm{2}}}{\rm{(\;g)}} \to {\rm{2Cl(g),}}\quad {\rm{242}}{\rm{.3\;kJ\;mo}}{{\rm{l}}^{{\rm{ - 1}}}}\)
\({{\rm{I}}_{\rm{2}}}{\rm{(\;g)}} \to {\rm{2I(g),151}}{\rm{.0\;kJ\;mo}}{{\rm{l}}^{{\rm{ - 1}}}}\)
\({\rm{ICl(g)}} \to {\rm{I(g) + Cl(g),211}}{\rm{.3\;kJ\;mo}}{{\rm{l}}^{{\rm{ - 1}}}}\)
\({{\rm{I}}_{\rm{2}}}{\rm{(\;s)}} \to {{\rm{I}}_{\rm{2}}}{\rm{(\;g),}}\quad {\rm{62}}{\rm{.76\;kJ\;mo}}{{\rm{l}}^{{\rm{ - 1}}}}\)
Given that the standard states for iodine and chlorine are \(\mathrm{\mathrm{I}_{2}(\mathrm{~s})}\) and \(\mathrm{\mathrm{Cl}_{2}(\mathrm{~g})}\), the standard enthalpy of formation for \(\mathrm{\mathrm{ICl}(\mathrm{g})}\) is

1 \(\mathrm{-14.6 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
2 \(\mathrm{-16.8 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
3 \(\mathrm{+16.8 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
4 \(\mathrm{+244.8 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
CHXI06:THERMODYNAMICS

369538 If the bond energies of \(\mathrm{\mathrm{H}-\mathrm{H}, \mathrm{Br}-\mathrm{Br}}\) and \(\mathrm{\mathrm{H}-\mathrm{Br}}\) are 433, 192 and \(\mathrm{364 \mathrm{~kJ} \mathrm{~mol}^{-1}}\) respectively, then \(\mathrm{\Delta \mathrm{H}^{\circ}}\) for the reaction:
\(\mathrm{\mathrm{H}_{2(\mathrm{~g})}+\mathrm{Br}_{2(\mathrm{~g})} \rightarrow 2 \mathrm{HBr}_{(\mathrm{g})}}\) is

1 \(\mathrm{-261 \mathrm{~kJ}}\)
2 \(\mathrm{+103 \mathrm{~kJ}}\)
3 \(\mathrm{+261 \mathrm{~kJ}}\)
4 \(\mathrm{-103 \mathrm{~kJ}}\)
CHXI06:THERMODYNAMICS

369539 The enthalpy of atomisation for the reaction \(\mathrm{\mathrm{CH}_{4(\mathrm{~g})} \rightarrow \mathrm{C}_{(\mathrm{g})}+4 \mathrm{H}_{(\mathrm{g})}}\) is \(\mathrm{1665 \mathrm{~kJ} \mathrm{~mol}^{-1}}\). The bond energy of \(\mathrm{\mathrm{C}-\mathrm{H}}\) bond is

1 \(\mathrm{832.5 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
2 \(\mathrm{416.2 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
3 \(\mathrm{1665 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
4 \(\mathrm{208.1 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
CHXI06:THERMODYNAMICS

369540 The bond dissociation energies of \(\mathrm{X_{2}, Y_{2}}\) and \(\mathrm{X Y}\) are in the ratio of \(\mathrm{1: 0.5: 1 . \Delta H}\) for the formation of \(\mathrm{X Y}\) is \(\mathrm{-200 \mathrm{~kJ} \mathrm{~mol}^{-1}}\). The bond dissociation energy of \(\mathrm{X_{2}}\) will be

1 \(\mathrm{800 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
2 \(\mathrm{400 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
3 \(\mathrm{100 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
4 \(\mathrm{200 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
CHXI06:THERMODYNAMICS

369541 In the dissociation of \(\mathrm{\mathrm{CH}_{4}(\mathrm{~g})}\),

1 Bond energies of all the \(\mathrm{\mathrm{C}-\mathrm{H}}\) bonds are equal
2 No two bonds have equal energy
3 Two bonds have equal energy
4 Three bonds have equal energy
CHXI06:THERMODYNAMICS

369542 The enthalpy changes for the following processes are listed below
\({\rm{C}}{{\rm{l}}_{\rm{2}}}{\rm{(\;g)}} \to {\rm{2Cl(g),}}\quad {\rm{242}}{\rm{.3\;kJ\;mo}}{{\rm{l}}^{{\rm{ - 1}}}}\)
\({{\rm{I}}_{\rm{2}}}{\rm{(\;g)}} \to {\rm{2I(g),151}}{\rm{.0\;kJ\;mo}}{{\rm{l}}^{{\rm{ - 1}}}}\)
\({\rm{ICl(g)}} \to {\rm{I(g) + Cl(g),211}}{\rm{.3\;kJ\;mo}}{{\rm{l}}^{{\rm{ - 1}}}}\)
\({{\rm{I}}_{\rm{2}}}{\rm{(\;s)}} \to {{\rm{I}}_{\rm{2}}}{\rm{(\;g),}}\quad {\rm{62}}{\rm{.76\;kJ\;mo}}{{\rm{l}}^{{\rm{ - 1}}}}\)
Given that the standard states for iodine and chlorine are \(\mathrm{\mathrm{I}_{2}(\mathrm{~s})}\) and \(\mathrm{\mathrm{Cl}_{2}(\mathrm{~g})}\), the standard enthalpy of formation for \(\mathrm{\mathrm{ICl}(\mathrm{g})}\) is

1 \(\mathrm{-14.6 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
2 \(\mathrm{-16.8 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
3 \(\mathrm{+16.8 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)
4 \(\mathrm{+244.8 \mathrm{~kJ} \mathrm{~mol}^{-1}}\)