Please explain the process, i don't understand what to do! Problem: A substance has the empirical formula of CH2Br and a molar mass of 188 g mol -1. What is the molecular formula of the compound?

Question

anonymous · Answer

Basically, the formula itself is "CH2Br" which will not change, the molar mass tells you the weight of the overall molecule. If you add up Molecular weight of 1 bromine, 1 carbon, and 2 hydrogen. It should give you a molar mass. All you have to do is see how many molecules of this "CH2Br" you need to have a molar mass (molecular weight) of 188. Does this help any?

anonymous · Answer

you need to calculate "n" and then multiply that value with your empirical formula.

n=molecular mass/empirical formula mass
n=180/78.04
n=2.3 now make it to whole 
to make it whole number multiply 2.3 by 1.3 so 
n=3