How many grams of oxygen can be obtained by decomposition of 49 g of berthollet’s salt.

To solve the problem, let’s compose an equation, select the coefficients:
2KClO3 = 3O2 + 2KCl – decomposition reaction, oxygen is released;
Let’s calculate the molar masses of substances:
M (KClO3) = 122.6 g / mol;
M (O2) = 32 g / mol.
Let us determine the number of moles of berthollet salt:
Y (KClO3) = m / M = 49 / 122.6 = 0.389 mol.
Let’s make the proportion:
0.389 mol (KClO3) – X mol (O2);
-2 mol -3 mol from here, X mol (O2) = 0.389 * 3/2 = 0.598 mol.
We find the mass of oxygen:
m (O2) = Y * M = 0.598 * 32 = 19.15 g.
Answer: the mass of oxygen is 19.15 g.