Question

HELP PLEASE 13. (4 points) Sodium and water react according to the following equation. If 31.5g of sodium are added to excess water, how many liters of hydrogen gas are formed at STP? Show all work for credit.

2Na + 2H2O --> 2NaOH + H2

Answer 1

The molecular weight of sodium is 23gr/mol. There is 31.5g sodium react used for reaction. From the equation, you can conclude that for every 2 sodium atoms, there will be 1 H2 gas formed.
The number of the H2 gas molecule formed would be: (2/1) * 31.5g/(23g/mol) = 2.74 mol

In STP an ideal gas will have volume 22.4l/mol. The volume of H2 gas would be: 22.4 l/mol * 2.74 mol= 61.36 liters.