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.
Decomposing because it was being eaten to be decomposed into particles.<span />
Mechanical, because the other two make no sense and mechanical energy is the combination of kinetic and potential energy, or moving and still respectively.
There are several ways to visually represent compounds. For this particular organic compound, we can use the skeletal formula and the expanded formula. The skeletal makes use of lines to show which atoms are bonded to each other. The expanded formula shows the species of the atoms and their bonding with other atoms. I have attached the two representations.
The percentage by mass of oxygen in the compound
find the total mass=( 1.900+ 0250 +0.850) = 3
the percentage mass mass of oxgyen/total mass x100
that is (0.850/3) x100=28.33%