# Calculate the mass of berthollet’s salt required to obtain a 40 g portion of oxygen.

September 22, 2021 | education

| To solve, we write down the reaction equation:

2KClO3 = 3O2 + 2KCl – decomposition reaction of berthollet salt, oxygen is released;

We calculate the molar masses of substances:

M (KClO3) = 112.6 g / mol;

M (O2) = 32 g / mol;

Determine the amount of moles of oxygen by the formula:

Y (O2) = m / M = 40/32 = 1.25 mol.

According to the equation, we will compose the proportion:

X mol (KClO3) – 1.25 mol (O2);

-2 mol -3 mol from here, X mol (KClO3) = 2 * 1.25 / 3 = 0.83 mol.

Find the mass of KClO3:

m (KClO3) = Y * M 0.83 * 122.6 = 101.75 g.

Answer: the mass of the berthollet salt is 101.75 g.

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