Question

40.2 grams of Hydrogen Chloride (HCl) is decomposed. 12 grams of Chlorine (Cl) is formed. How many grams of Water (H2O) was formed?

Answer 1

3.05 g

Step-by-step explanation:

The reaction that takes place is:

• 4HCl + O₂ → 2Cl₂ + 2H₂O

As the decomposition not necessarily was complete we'll work with the given mass of product formed. We convert the 12 grams of chlorine to moles, using its molar mass:

• 12 g ÷ 70.906 g/mol = 0.169 mol

Then we convert Cl₂ moles to H₂O moles:

• 0.169 mol Cl₂ *
  `(2molH_2O)/(2molCl_2)` = 0.169 mol H₂O

Finally we convert moles to grams:

• 0.169 mol H₂O * 18 g/mol = 3.05 g