We have to covert 512 cal of heat in kilo joules.
As, 1 cal = 0.004184 kJ = 4.184 joules.
Therefore,
[tex]512 \ cal = 512 \times 4.184 \ J = 2142.208 \ J \\\\\ = 2.142 \times 10 ^3 J = 2.142 \ kJ[/tex]
Thus, combustion of a small wooden match produces approximately ( in kilo joules ) is 2.142 kJ .