Question

if 2.0 g of H reacts with 16 g of O to form H2O, then how many grams of oxygen with react with H to form H2O2?

Answer 1

Answer:

16g

Explanation:

Given parameters:

Mass of H₂   = 2.0g

Mass of O₂ = 16g

Unknown:

Mass of oxygen that will react to form H₂O₂  = ?

Solution:

Let us establish the reaction equation first;

              H₂  + O₂   →    H₂O₂

This equation is balanced chemical equation;

   Now to solve this problem, find the limiting reactant. The limiting reactant is the reactant in short supply.

To find this reactant, convert the given masses to number of moles.

   Number of moles   = $\frac{mass}{molar mass}$

         Molar mass of H₂  = 2(1)  = 2g/mol

          Molar mass of  O₂  = 2(16) = 32g/mol

 Number of moles of H₂  = $\frac{2}{2}$   = 1mole

 Number of moles of O₂   = $\frac{16}{32}$   = 0.5mole

  From the balanced reaction equation;

     

         1 mole of H₂  reacted with 1 mole of O₂

Therefore 1 mole of H₂ will require 1 mole of O₂

But the given number of O₂ is 0.5moles. This is the limiting reactant that will determine the extent of the reaction.

  The mass of 0.5moles of oxygen gas is 16g