<span>Combustion means the elements or compound can be burned, but burning which is a chemical process requires oxygen; combustion reaction typically takes place in the presence of air. The combustion of methane is as follows:
CH4(g) + 2 O2(g) -> CO2(g)+ 2 H2O(g) + energy
One mole of gaseous methane reacts with two oxygen molecules to form a carbon dioxide molecule, and two water molecules which is given off as water vapor. The reaction involves the release of heat.</span>
When CH₄ is burnt in excess O₂ following products are formed,
CH₄ + 2 O₂ → CO₂ + 2 H₂O
According to equation 1 mole of CH₄ (16 g) reacts with 2 moles of O₂ to produce 1 mole of CO₂ and 2 moles of H₂O. Hence the products are,
1 mole of CO₂ and 2 moles of H₂O
Converting 1 mole CO₂ to grams;
As,
Mass = Moles × M.mass
Mass = 1 mol × 44 g.mol⁻¹
Mass = 40 g of CO₂
Converting 2 moles of H₂O to grams,
Mass = 2 mol × 18 g.mol⁻¹
Mass = 36 g of H₂O
Total grams of products;
Mass of CO₂ = 44 g
+ Mass of H₂O = 36 g
-------------
Total = 80 g of Product
Result:
80 grams of product is formed when 16 grams of CH₄ is burnt in excess of Oxygen.
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The amount of energy released is calculated by the product of heat of fusion and mass.
The formula of amount energy released is given by:
(1)
Here,
q is amount of energy released
L is heat of fusion (
)
m is mass of water
Put all the given values in equation (1)
≅ 
Thus, amount of energy released is 
