Concerning the 10.0 mL of 0.50 M NaCl to 100 mL of solution: When a solution is diluted, does it change the number of moles dissolved?

no ...

No, the dilution does not change the number of moles dissolved

Explanation:

We can see that,

The molarity of the solution was 0.50 M

The volume of the solution is 10 ml.

No of moles of the solute was = volume * concentration

= 10 X 10^-3 * 0.50

= 5*10^-3 moles

When the solution is diluted from 10 ml to 100ml, the molarity or concentration changes but number of moles remains constant.

The molarity of 100 ml solution will be

c=n/V

= 5*10^-3*/100*10^-3

= 0.05

when the solution is diluted to 100ml from 10 ml molarity changes from 0.5M TO 0.05 M