1H NMR - Counting environments for hydrogen
The principles for predicting the number of nonequivalent environments for 1H are similar to predicting the number of 13C environments. 
Hydrogens bonded to the same carbon
are in the same environment.*
There are five different environments for 2-chloropentane.
Hydrogens bonded to different carbons are in the same environment if the carbons are in the same environment.
There are three different environments for 3-chloropentane.
The number of environments for hydrogen does not necessarily equal the number of environments for carbon because some carbons do not bear any hydrogens. *You will encounter exceptions to this in more advanced courses.