ThermochemistryHard
Question
If the bond dissociation energies of XY, X2 and Y2 (all diatomic molecules) are in the ratio of 1:1:0.5 and ᐃfH for the formation of XY is -200 kJ mole-1. The bond dissociation energy of X2 will be
Options
A.100 kJ mole-1
B.200 kJ mole-1
C.300 kJ mole-1
D.400 kJ mole-1
Solution
(None of the options is correct.)
XY → X(g) + Y(g) ; ᐃH = + a kJ /mole ........(i)
X22X ; ᐃH = + a kJ/mole ........(ii)
Y22Y ; ᐃH = + 0.5 a kJ/mole ........(ii)
× (ii) + × (iii) - (i), Gives
Y2 → XY ; ᐃH = 
kJ / mole
- a = - 200
a = 800.
XY → X(g) + Y(g) ; ᐃH = + a kJ /mole ........(i)
X22X ; ᐃH = + a kJ/mole ........(ii)
Y22Y ; ᐃH = + 0.5 a kJ/mole ........(ii)
× (ii) + × (iii) - (i), Gives Y2 → XY ; ᐃH = kJ / mole - a = - 200 a = 800.
Create a free account to view solution
View Solution FreeMore Thermochemistry Questions
50.0 mL of 0.10 M HCl is mixed with 50.0 mL of 0.10 M NaOH. The solution′s temperature rises by 3.0oC. Calculate t...The standard enthalpies of formation of H2O(l), Li+ (aq) and OH− (aq) are −285.8, −278.5 and −228.9 kJ/mol, respectively...Study the following thermochemical data.S + O2 → SO2: ΔH = −298.2 kJSO2 + ½ O2 → SO3: ΔH = −98.2 kJSO3 + H2O → H2SO4: ΔH...The Δf Ho for CO2(g), CO(g) and H2O(g) are −393.5, −110.5 and −241.8 kJ mol–1, respectively. The standard enthalpy chang...From the following data, calculate the enthalpy change (in kJ/mol) for the combustion of cyclopropane(g) at 298 K. The e...