Question

A solution of KClO3 is prepared using 75 grams of the solute in enough water to make 0.250 liters of solution. The gram-formula mass of KClO3 is 122 grams per mole.

Determine the molarity (concentration in mol/L) of the solution.
Assuming the solution is saturated, determine the temperature of the solution.

Answer 1

Question#74968 – Chemistry – General Chemistry

Question: A solution of $\mathrm{KClO}_3$ is prepared using 75 grams of the solute in enough water to make 0.250 liters of solution. The gram-formula mass of $\mathrm{KClO}_3$ is 122 grams per mole. Determine the molarity (concentration in mol/L) of the solution. Assuming the solution is saturated, determine the temperature of the solution.

Solution:

1. Find moles of $\mathrm{KClO}_3$.

$$\mathrm{n}(\mathrm{KClO}_3) = \frac{75\ \mathrm{g}}{122\ \frac{\mathrm{g}}{\mathrm{mol}}} = 0.615\ \mathrm{mol}$$

2. Find a concentration:

$$C_M = \frac{0.615\ \mathrm{mol}}{0.250\ \mathrm{L}} = 2.46\ \mathrm{M}$$

3. Find a solubility (in g/100 H₂O):

$$\mathrm{m}(H_2\mathrm{O}) = 250\ \mathrm{g}$$ $$s = \frac{75\ \mathrm{g}}{250\ \mathrm{g}\ \mathrm{H}_2\mathrm{O}} \times 100\ \mathrm{g}\ \mathrm{H}_2\mathrm{O} = 30\ \mathrm{g}/(100\ \mathrm{g}\ \mathrm{H}_2\mathrm{O})$$

4. Find the temperature of the solution from solubility curve:

T≈68°C

Answer:

$$C_M = 2.46\ \mathrm{M}$$ $$T \approx 68^{\circ} \mathrm{C}$$

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