Calculation of Mass of Potassium Nitrate for Saturated Solution

Potassium nitrate is a salt that readily dissolves in water. The solubility of potassium nitrate in water increases with temperature. At 313 K, the solubility of potassium nitrate in water is approximately 40 g/100 mL. Therefore, to prepare a saturated solution of potassium nitrate in 50 grams of water at 313 K, we need to calculate the mass of potassium nitrate required.

Formula to Calculate Mass of Potassium Nitrate for Saturated Solution

The formula to calculate the mass of potassium nitrate required to prepare a saturated solution in a given amount of water is:

Mass of solute (potassium nitrate) = solubility x volume of solvent (water)

In this case, the volume of water is 50 mL or 50 g. Therefore,

Mass of solute (potassium nitrate) = 40 g/100 mL x 50 mL

Mass of solute (potassium nitrate) = 20 g

Therefore, 20 grams of potassium nitrate would be required to prepare a saturated solution in 50 grams of water at 313 K.

Explanation

The solubility of a salt in a given amount of solvent is the maximum amount of the salt that can dissolve in the solvent at a given temperature. In this case, the solubility of potassium nitrate in water at 313 K is 40 g/100 mL. This means that at this temperature, 40 grams of potassium nitrate can dissolve in 100 mL of water. To prepare a saturated solution, we need to dissolve the maximum amount of potassium nitrate that can dissolve in the given amount of water. Therefore, we use the formula for the mass of solute required to prepare a saturated solution.