Question

The equation for the reaction between magnesium and hydrogen is written below
mg+2hcl------mgcl (2)+H (2)
(1) what mass of magnesium would be needed to give 50g of hydrogen? (mg=24, H=1)
(2) what volume would this gas occupy at s.t.p​

Answer 1

Answer:

Explanation:

The balanced equation says that we'll get 1 mole of H2 for every 1 mole of Mg.  50 grams of H is 50g/2 g/mole = 25 moles of H2.  That means we'll need 25 moles of Mg.  Convert that into grams:  (25 moles Mg)*(24.3 g/mole) = 607 grams Mg.  

At STP, all gases occupy 22.4 liters/miole.  That means 25 moles of H2 would occupy (25 moles)*(22.4 liters/mole) = 560 liters.