When one mole of gaseous methane s burnt in excess of gaseous oxygen, 890 kJ of heat is evolved in addition to the formation of gaseous CO_(2) and liquid water. (a) Write the thermochemical equation for this reaction. (b) Calculate the amount of heat evolved when 10 grams of methane is burnt.

When one mole of gaseous methane s burnt in excess of gaseous oxygen,

1.	When one mole of gaseous methane s burnt in excess of gaseous oxygen, 890 kJ of heat is evolved in addition to the formation of gaseous CO_(2) and liquid water. (a) Write the thermochemical equation for this reaction. (b) Calculate the amount of heat evolved when 10 grams of methane is burnt.
Answer» SOLUTION :(a) `CH_(4)(g) + 2O_(2)(g) rarr CO_(2)(g) + 2H_(2)O(l)Delta H = -890 KJ` (b) From the equation `1 " mole of "CH_(4) = 16g = 890 kJ " heat"` `16g CH_(4)` RELEASES `= 890 kJ` heat `10 g CH_(4)` releases `= (890 kJ xx 10 g)/(16g) = 556 kJ` Amount of heat liberated for the combustion of 10 g `CH_(4) = 556 kJ`.