Question

A gas with an empirical formula C2H2O has a molecular weight of 120.6g/mol. A possible molecular formula for the gas is

A) CH2O
B) C2H2O
C) C3H6O1.5
D) C6H6O3
E) C4H4O2

Answer 1

M(C2H2O)= 12.0*2 +1.0*2 +16.0 = 42 g/mol is a molar mass for empirical formula.

120.6g/mol/42g/mol ≈ 3

So, empirical formula should be increased 3 times,

and molecular formula is C6H6O3.

Answer is D.