Question

2Na+S→Na2S

What is the total number of moles of S that react when 4.0 moles of Na were completely consumed?​

Answer 1

2.0 moles S

Step-by-step explanation:

To find the number of moles of S, you need to convert the moles Na to moles S via the mole-to-mole ratio. This ratio is represented by the coefficients in the balanced equation. Because you wish to find moles S, you want to put this number in the numerator. Because you want to eliminate the moles Na, this number should be in the denominator.

2 Na + 1 S ---> Na₂S

4.0 moles Na 1 mole S
---------------------- x --------------------- = 2.0 moles S
2 moles Na