Methane reacts with oxygen to produce carbon dioxide water and heat. how many kcal are produced when 5.00 g of methane react

=  66.33 kCal

Explanation:

The combustion of methane is given by the equation;

CH4(g) + 2O2(g) → CO2(g) + 2H2O(l); ΔH = -890.3 kJ/mol

The molar enthalpy of combustion of methane is -890.3 kJ/mol

This means 1 mole of CH4 yields 890.3 kJ/Mol

But, molar mass of methane is 16.04 g/mol

Therefore;

Heat produced by 5.0 g of methane will be;

= (5.0 g/ 16.04 g/mol)× 890.3 kJ/mol

= 277.525 kJ/mol

But; 1 kcal = 4.184 kJ

thus; = 277.525 /4.184

         =  66.33 kCal