Question

5. Given the reaction:
2 H2 + O2 + 2 H2O
The total number of grams of O2 needed to produce
54 grams of water is
48

Answer 1

Answer:

48 g of oxygen is needed to produced 54 g of water.

Explanation:

Given data:

Mass of O₂ = ?

Mass of H₂O = 54 g

Chemical equation:

O₂  + 2H₂  → 2 H₂O

Number of moles of H₂O:

Number of moles of  H₂O= Mass /molar mass

Number of moles of H₂O= 54 g / 18/mol

Number of moles of  H₂O= 3 mol

Now we will compare the moles of water with  oxygen .

                 H₂O             :            O₂

                  2                 :             1

                  3                  :            1/2 × 3 =1.5

              

The 3 moles of H₂O produced by 1.5 moles of oxygen.

Mass of O₂  :

Mass of O₂  :  = number of moles × molar mass

Mass of O₂  : = 1.5 mol ×32 g/mol

Mass of O₂  :  = 48 g