Calculate the volume of oxygen that can be obtained by decomposing a 490 g berthollet salt.

Given:
m (KClO3) = 490 g;
V (O2) =?
Decision:
Let us write the reaction equation taking into account the presence of a catalyst:
KClO3 → 2KCl + 3O2.
Let’s write down the basic formulas that will be used:
n = m / M;
V = n * VM.
We calculate M (KClO3) = 39 + 35.5 + 3 * 16 = 122.5 (g / mol).
We get n (KClO3) = 490 / 122.5 = 4 (mol).
Taking into account the ratio of the amount of salt and oxygen in the equation, we find that n (O2)> n (KclO3) 3 times. Hence, n (O2) = 3 * 4 = 12 (mol).
Let’s calculate the volume of oxygen:
V (O2) = 12 * 22.4 = 268.8 (L).
Answer: the volume of oxygen is 268.8 liters.