When .500 mole of sodium is produced according to the reaction 2NaN3->3Na+Na, how many moles of Nitrogen gas are also produced?

Your equation is not good.

Is it:

Na_3N \rightarrow Na + N_2

Then, balance your equation to give:

2Na_3N \rightarrow 3Na + N_2

From here, you know that when 3 moles of Na are produced, you also get 1 mole of nitrogen gas.

Use proportions to find the number of moles of Nitrogen gas produced when 0.5 moles of Na are produced.

3 moles Na -> 1 mole N2
1 mole Na -> 1/3 mole N2
0.5 mole Na -> ? Moles N2