How can I calculate the percent composition of C2H8N?

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Answer 1 · 2014-06-04T22:44:03

To find the percent composition of C₂H₈N, you divide the total mass of each atom by the molecular mass and multiply by 100 %.

% by mass = #"mass of component"/"total mass"# × 100 %

Mass of 2 C atoms = 2 C atoms × #(12.01"u")/(1"C atom")# = 24.02 u.

Mass of 8 H atoms = 8 H atoms × #(1.008"u")/(1"H atom")# = 8.064 u

Mass of 1 N atom = 1 N atom × #(14.01"u")/(1"O atom")# = 14.01 u

Mass of 1 C₂H₈N molecule = (24.02 + 8.064 + 14.01) u = 46.09 u

% of C = #"mass of C"/"total mass"# × 100 % = #(24.02"u")/(46.09"u")# × 100 % = 52.11 %

% of H = #"mass of H"/"total mass"# × 100 % = #(8.064"u")/(46.09"u")# × 100 % = 17.49 %

% of N = #"mass of N"/"total mass"# × 100 % = #(14.01"u")/(46.09"u")# × 100 % = 30.39 %