Compute the heat of formation of liquid methyl alcohol in kilojoules per mole, using the following data. Heat of vapourisation of liquid methyl alcohol= 38 kJ/mol. Heat of formation of gaseous atoms from the elements in their standard states, H= 218kJ/mol, C= 715 kJ/mol, O= 249 kJ/mol. Average bond energies, C-H = 415 kJ/mol, C-O = 365 kJ/mol, O-H= 463 kJ/mol

Compute the heat of formation of liquid methyl alcohol in kilojoules p

1.	Compute the heat of formation of liquid methyl alcohol in kilojoules per mole, using the following data. Heat of vapourisation of liquid methyl alcohol= 38 kJ/mol. Heat of formation of gaseous atoms from the elements in their standard states, H= 218kJ/mol, C= 715 kJ/mol, O= 249 kJ/mol. Average bond energies, C-H = 415 kJ/mol, C-O = 365 kJ/mol, O-H= 463 kJ/mol
Answer» Solution :`C_((s)) rarr C_((g)) , Delta H_(1) = 715` `(1)/(2) H_(2) rarr H, Delta H_(2) = 218` `(1)/(2) O_(2) rarr O, Delta H_(3) = 249` `C_((s)) + 2H_(2) + (1)/(2) O_(2) rarr C_((g)) + 4H_((g)) + O_((g)), Delta H_(4) = 1836` `C_((g)) + 4H_((g)) + O_((g)) rarr CH_(3)OH_((L)), Delta H = 1836 - [1 xx (C - O) + 3 xx (C - H) + 1 xx (O-H)] - Delta H_("VAP")` `=1836 - (365 + 3 xx 415 + 463 + 38)` `= 1836 - 2111 = -275` KJ/mole `rArr - 55 xx 5`