Following are three possible reactions that could occur when a sample of KClO3 (s) is heated. One goal of this lab is to determine the correct one. Balance all three reactions. a. ___ KClO3 (s) ___ KClO2 (s) + O2 (g) b. ___ KClO3 (s) ___ KClO (s) + O2 (g)
c. ___ KClO3 (s) ___ KCl (s) + O2 (g)

2KClO3 (s)  → 2KCl (s) + 3O2 (g)  (option C)

Explanation:

Step 1:

a. ___ KClO3 (s) → ___ KClO2 (s) + O2 (g)

On the left side we have 3x O (in KClO3) and on the right side we have 4x O (2x in KClO2 and 2x in O2). To balance the amount of O on both sides, we have multiply KClO3 and KClO2 by 2.

2KClO3 (s) → 2KClO2 (s) + O2 (g)

This is not the reaction that occurs when KClO3 is heated

b. ___ KClO3 (s) ___ KClO (s) + O2 (g)

This equation is already balanced

KClO3 (s) → KClO (s) + O2 (g)

c. ___ KClO3 (s) ___ KCl (s) + O2 (g)

On the left side we have 3x O (in KClO3) and on the right side we have 2x O (in O2). To balance the amount of O on both sides, we have multiply KClO3 by 2 and O2 by 3.

On the left side we have 2x K (in 2KClO3) and on the right side we have 1x K (in  KCl). To balance the amount of K on both sides, we have multiply KCl on the right side by 2.

2KClO3 (s)  → 2KCl (s) + 3O2 (g)

When KClO3 is heated strongly, it breaks down, releasing oxygen gas and leaving behind a thermally stable (i.e., heat-insensitive) solid residue of an ionic potassium compound, as KCl

Option C is the correct answer

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fe 55.85 g/mol and h2o 18.02 g/mol.