What is the molecular formula of a compound that has a molecular mass of 54 and the empirical formula #C_2H_3#?

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Answer 1 · 2017-05-14T10:08:59

#C_4H_6#.............

The #"molecular formula"# is always a whole number multiple of the #"empirical formula"#.

i.e. #"molecular formula"=nxx("empirical formula")#

#54*g*mol^-1=nxx(2xx12.011+3xx1.00794)*g*mol^-1#

#=nxx(27.04)*g*mol^-1#

Clearly, #n=(54.0*g*mol^-1)/(27.04*g*mol^-1)=2#

#"Molecular formula"=(C_2H_3)xx2=C_4H_6# as required.

This compound has two degrees of unsaturation, so it is a butadiene, or a cylocbutene, or an allene derivative, or an alkyne.........