Question

A chemist is trying to determine the molar mass of an unknown substance. What is the molar mass of this substance if she finds that 30.8 g contains 7.180x10^23 molecules?

I know the answer is 25.8, but I need to know the work needed to be done to get there.

Answer 1

Step-by-step explanation:

n=m/M=N/Na

where m represents mass

M represents molar mass

N represents Number of molecules

Na is avogadros constant which is denoted as 6.02*10^23

30.8/M=7.180*10^23/6.02*10^23

30.8/M=1.1927

M=30.8/1.1927=25.1g/mol