Answer:
Molecular formula = C₂H₆
Explanation:
Given data:
Percentage of hydrogen = 20.0 %
Percentage of carbon = 80.0 %
Molar mass = 30.0 g
Empirical formula = ?
Solution:
Number of gram atoms of H = 20 / 1.01 = 19.8
Number of gram atoms of C = 80 /12 = 6.7
Atomic ratio:
C : H
6.7/6.7 : 19.8/6.7
1 : 3
C : H = 1 : 3
Empirical formula is CH₃.
Molecular formula:
Molecular formula = n (empirical formula)
n = molar mass of compound / empirical formula mass
Empirical formula = CH₃ = 12×1 +3×1.01 = 15.03 g/mol
n = 30 g/mol / 15.03 g/mol
n = 2
Molecular formula = n (empirical formula)
Molecular formula = 2 (CH₃)
Molecular formula = C₂H₆
