What is the mass % of oxygen in methanol?
A)16.0
B)12.0
C)50.0
D)4.00
E)32.0

Question

Quizplus · Accepted Answer

Methanol has the chemical formula CH3OH, which consists of one oxygen atom and four hydrogen atoms. The molar mass of methanol is 32.04 g/mol (12.01 g/mol for carbon + 4*1.01 g/mol for hydrogen + 16.00 g/mol for oxygen). The mass of oxygen in one mole of methanol is 16.00 g/mol. Therefore, the mass % of oxygen in methanol is:

(mass of oxygen/molar mass of methanol) x 100%
= (16.00 g/mol/32.04 g/mol) x 100%
= 49.98%
≈ 50.0% (rounded to one decimal point)

Therefore, the correct answer is choice C.

What Is the Mass % of Oxygen in Methanol