[abby.nuccio]

A compound with a molecular mass of 78g/mol contains the elements carbon and hydrogen in a ration of 1 carbon : 1 hydrogen.
What is the empirical formula for this compound?
What is the molecular formula for this compound?
What is the percent composition of carbon in this compound?

[Borek]

Please read the forum rules.

You have to show your attempts at solving the question to receive help. This is a forum policy.

[abby.nuccio]

I do not understand how to find the molecular formula from the given molecular mass. It tells me that the ratio is 1 to 1, so I am guessing that the empirical formula is simply CH. I do not know how to go from here. Does the molecular formula have to equal 78? Once I get the molecular formula I will know how to solve the percent composition.

[Arkcon]

I do not understand how to find the molecular formula from the given molecular mass. It tells me that the ratio is 1 to 1, so I am guessing that the empirical formula is simply CH.

Good.  Now, what is the molecular mass of CH?  How many of those would you need to equal 78 AMU?

I do not know how to go from here. Does the molecular formula have to equal 78?

Well, only because this problem say so.

Once I get the molecular formula I will know how to solve the percent composition.

Also good.

[abby.nuccio]

Okay, thank you!