4.9 g of potassium chlorate when heated produced1.92 g of oxygen and the residue left behind weighed 2.96 g.Show that these results illustrates the law of conservation of mass.
Please explain nicely.
Answers
Ans: Note: When 4.90 grams of KClO3 undergoes decomposition it will produce 1.92 grams of Oxygen and 2.98 grams of KCL.
Molecular weight of KClO₃ = 122.5 Molecular weight of KCl =74.5
Molecular weight of O₂ = 32
Balanced equation for the dissociation of KClO₃ 2KClO₃→ 2KCl + 3O₂ Multiply total equation by ‘2’. 2*(2KClO₃→ 2KCl + 3O₂) 4KClO₃→4KCl + 6O₂ (4*122.5) → (4*74.5 + 6*32) 490 grams → (298 grams + 192 grams=490 grams)
From the above data when 490 grams of KClO₃ under goes dissociation it produces 298 grams of KCl and 192 grams of O₂.
Based on above data
Given 4.90 grams of KClO₃→2.98 grams of KCl + 1.92 grams of O₂ 4.90grams of reactants → (2.98 + 1.92 = ) grams of products
Therefore mass of the reactants remains equal to mass of products.
Law of conservation of mass verified true for the above reaction.