How many water molecules are produced when 5.2g O2 are reacted

Total number of water molecules produced after the reaction is 1.956×10^22 molecules of water.

Explanation:

By the reaction

H2+ 1/2 O2 → H2O

Moles of O2 = 5.2\32

⇒1 mole of O2 produce 1  mole of H2O

  1 mole O2 will produce 2 mole  of H2O

Therefore, 5.2\32 mole will produce

⇒ Molecules of H2O  will be

          =

= 1.956×10^22 moleculesof H2O.

1. for the first question, we must find the mass of the anhydrous salt, mgso₄. the molar mass for mgso₄·7h₂o is 246.47 g/mol, while that of mgso₄ is 120.37 g/mol.7.834 g mgso₄·7h₂o * 1 mol mgso₄·7h₂o/246.47 g * 1 mol mgso₄/1 mol mgso₄·7h₂o * 20.37 g mgso₄/mol = 0.647 g mgso₄

2. mass of water = mass of sample - mass of anhydrous salemass of water = 7.834 - 0.647 = 7.19 gpercent water in hydrate = 7.19/7.834 * 100 = 91.74%