Question

Sodium chlorate (NaClO3(s)) dissociates, during moderate heating to produce solid sodium chloride (NaCl(s)) and gaseous oxygen (O2 (g)). A 3.4671 g of impure sodium chlorate was heated until the evolution of oxygen stopped. The mass of sample residue was subsequently found to be 2.9073 g. What wt% of the original impure sample was really sodium chlorate? Assume that no gases will be evolved from the impurities.

Answer 1

Answer on Question #56880 – Chemistry – General Chemistry

Question:

Sodium chlorate (NaClO3(s)) dissociates, during moderate heating to produce solid sodium chloride (NaCl(s)) and gaseous oxygen (O2 (g)). A 3.4671 g of impure sodium chlorate was heated until the evolution of oxygen stopped. The mass of sample residue was subsequently found to be 2.9073 g. What wt% of the original impure sample was really sodium chlorate? Assume that no gases will be evolved from the impurities.

Solution:

$$2 \mathrm{NaClO_3} = 2 \mathrm{NaCl} + 3 \mathrm{O_2}$$ $$m(O_2) = 3.4671 - 2.9073 = 0.5598 \, (\mathrm{g});$$ $$m(\mathrm{NaClO_3}) = 2 * 106.44 * 0.5598 / 32 * 3 = 1.2413 \, (\mathrm{g});$$ $$w(\mathrm{NaClO_3}) = 1.2413 / 3.4671 = 35.8 \, (\%);$$

Answer: 35.8 %

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