need chemistry help

Question

the following chemical equation has NOT been balanced

Na + H20 —> NaOH + H2

how many grams of sodium are needed to produce 0.250 moles of hydrogen gas?

Answer 1

The first step to solving this problem is to balance the chemical equation. There are more hydrogens on the right side of the equation so we need to increase the number of hydrogen on the left side. Our only option is to add another water though that makes 1 extra O and H that the right side. Adding a second NaOH can fix that and the extra Na added can be balanced by adding a second Na. This gives the following balanced equation,

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

With the balanced equation in hand the problem becomes much simpler. To produce .250 mol of H2 we need twice as many mol of Na or .500 mol. Then we need to multiply .500 mol by the molecular mass of Na which gives 11.5g