Answer :
The given question is incomplete. The complete question is:
How much heat is produced when 24.8 g of [tex]CH_4[/tex] is burned in excess oxygen gas
Given: [tex]CH _4 +2O_2\rightarrow CO_2+2H_2O[/tex] ΔH= −802 kJ.
Answer: 1243.1 kJ
Explanation:
Heat of combustion is the amount of heat released on complete combustion of 1 mole of substance.
Given :
Amount of heat released on combustion of 1 mole of methane = 802 kJ kJ/mol
According to avogadro's law, 1 mole of every substance occupies 22.4 L at NTP, weighs equal to the molecular mass and contains avogadro's number [tex]6.023\times 10^{23}[/tex] of particles.
1 mole of [tex]CH_4[/tex] weighs = 16 g
Thus we can say:
16 g of [tex]CH_4[/tex] on combustion releases heat = 802 kJ
Thus 24.8 g of [tex]CH_4[/tex] on combustion releases =[tex]\frac{802}{16}\times 24.8=1243.1kJ[/tex]
Thus heat released when 24.8 g of methane is burned in excess oxygen gas is 1243.1 kJ