The empirical formula of a compound is CH. The experimental molar mass is 78.12 g/mol. How do you determine the molecular formula of the compound?

1 Answer
anor277
Jan 19, 2017

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

Explanation:

And thus: #"molecular formula"=nxx"(empirical formula)"#.

We take the given empirical formula, work out its mass, and then solve for #n#.

So #78.23*g*mol^-1=nxx(12.011+1.00794)*g*mol^-1#

Where of course, #12.011# and #1.00794# are the atomic masses of carbon and hydrogen in #g*mol^-1#,

#n=(78.23*g*mol^-1)/((12.011+1.00794)*g*mol^-1)=6#

And thus the molecular formula #-=# #(CH)_6# or #C_6H_6#. What is the likely name of this molecule?

Related questions
See all questions in Empirical and Molecular Formulas
Impact of this question
27279 views around the world
You can reuse this answer
Creative Commons License