Question

For which compound does 0.256 mole weigh 12.8 g?

A) \(C_2 H_4 O\)
B) \(CO_2\)
C) \(CH_3 Cl\) <--answer
D) \(C_2 H_6\)
E) None of these

can someone tell me why C is the right answer and not E?,

Answer 1

Number of moles =
`(mass (g))/(Molar mass)`
so to calculate molar mass (Molecular weight of compound):
Molecular weight =
`(mass (g))/(number of moles)`
=
`(12.8 g)/(0.256 mole)` = 50 g / mole
Now we calculate molecular weight of each compound in choices:
a) C₂H₄O = 44
b) CO₂ = 44
c) CH₃Cl = 50.4 ALMOST 50 so this is the correct answer
d) C₂H₆ = 30