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

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

Explanation:

Given dа ta:

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