Answer:
1. Percentage composition O in CO₂ is 72.7%
2.Percentage composition of O in N₂O₅ is 74.1%
Step-by-step explanation:
How to calculate percentage composition
I. Calculate the molar mass of the compound by summing up the atomic masses of the elements that makes up the compound
II. The percentage composition of the element is derieved by dividing the atomic mass of the atoms by the molar mass of the compound
III. Now express this ratio as a percentage.
1. Percentage composition of Oxygen in CO₂:
Molar mass of CO₂
Atomic mass of C = 12gmol⁻¹
Atomic mass of O = 16gmol⁻¹
Note: We have two atoms of Oxygen
Molar mass = [12 + (2x16)]gmol⁻¹
= (12 + 32)gmol⁻¹
= 44gmol⁻¹
Percentage composition O in CO₂
= (2x16)/44 x 100
= 32/44 x 100
= 0.727 x 100
= 72.7%
Percentage composition O in CO₂ is 72.7%
2. The percentage composition of O in N₂O₅
Atomic mass of N = 14gmol⁻¹
Atomic mass of O = 16gmol⁻¹
Molar mass of N₂O₅ = [(2x14) + (5x16)]gmol⁻¹
= (28 + 80)gmol⁻¹
= 108gmol⁻¹
Percentage composition of O in N₂O₅
= (5x16)/108 x 100
= 80/108 x 100
= 0.741 x 100
= 74.1%
Percentage composition of O in N₂O₅ is 74.1%
Note: Percentage composition is expressed as a percentage.