Question

10. Given the themochemical equation for the combustion of methanol.

2 CH3OH(g) + 3 O2(g) ® 2 CO2(g) + 4 H2O(l) DrH = −1453 kJ/mol reaction

d. Review the units “kJ/mol reaction”. What does “mole reaction” mean?

e. If you produce 857 kJ of heat, how many “mole reactions” occurred?

f. Relate the energy of the “mole reaction” to moles of methanol and determine the mass (in grams) of methanol needed.

Answer 1

d) -1453 kJ/mole reaction means 1454 kJ of heat is released when one mole of methanil is completely combusted in excess of oxygen or air

e) If 857 kJ of heat is produced means that

When one mole is completely combusted in excess of oxygen 1453 kJ of heat is produced.

1453 kJ of heat produced - one mole is combusted

857 kJ of heat is produced when how many moles of methanol combusted

=

f) Mass of methanol required for producing 857 kJ of energy is

Gram molecular weight of methanol is 1×12+1×4+1×16= 32 gram/mole

1 mole = 32 grams

0.59 moles = ? Grams

0.59×32 = 18.87 grams = 18.9 grams