A sample of sodium reacts completely with 0.568 of chlorine, forming 936 of sodium chloride. What mass of sodium reacted?

Answer 1

0.568 what?
936 what?
After you fill in the units you will have a stoichiometry problem. Here is a worked example of such a problem; just follow the steps.
http://www.jiskha.com/science/chemistry/stoichiometry.html

Answer 2

A sample of sodium reacts completely with 0.568 kg of chlorine, forming 936 g of sodium chloride. What mass of sodium reacted?
the value and Units