How many grams of H2O are formed from 7.8 grams of O2?

Mass = 7.2 g

Explanation:

Given dа ta:

Mass of water produced = ?

Mass of oxygen = 7.8 g

Solution:

Chemical equation:

2H₂ + O₂ → 2H₂O

Number of moles of oxygen:

Number of moles = mass / molar mass

Number of moles = 7.8 g / 32 g/mol

Number of moles = 0.2 mol

Now we will compare the moles of water with oxygen.

O₂ : H₂O

1 : 2

0.2 : 2*0.2 = 0.4 mol

Mass of water:

Mass = number of moles * number of moles

Mass = 0.4 mol * 18 g/mol

Mass = 7.2 g