Question

If you have 10.0 g of hydrogen and 5.0 g of oxygen, what mass of the excess reagent remains after the completion of the reaction?

Answer 1

mass Hydrogen=9.376 g

Further explanation

Reaction

2H₂+O₂⇒2H₂O

mass H₂ = 10 g

mol H₂(MW=2 g/mol) :

 10 : 2 = 5

mass O₂=5 g

mol O₂(MW=32 g/mol) :

 5 : 32 = 0.156

O₂ limiting reactant

mol H₂: mol O₂ = 2: 1, so mol H₂ :

 2 x 0.156 = 0.312

mol H₂ :

5 - 0.132 =4.688  

mass of H₂ :

4.688 x 2 =9.376 g