Question

Post-Laboratory Questions 1 What procedural change for this experiment would be necessary if the solubility of the s wew initialy determined at 10 C, followed by solubility determinations at 20 C. 35 C, , and 80 C 2. Use the information in Figure 1 to determine the temperature at which 10.0 g KNO, dissolved in 12.5 mL of H:O would be a saturated solution 3. While transferring the weighed salt to the test tube during this experiment, a student spilled some. Will this salt loss result in calculated salt solubilities that are too high, too low, or unchanged? Briefly explain.

can someone help me solve these problems ?

Answer 1

1)

Take 6 test tubes here instead of one with same amount of solvent and and add some amount of solute to each. And measure the solubility at the pariticular temperature by slowly adding solute to the solvent. Till it comes saturation..then measure the recrystallisatiin .The calculated amount of solute dissolved from the amount of solute is added. Constant stirring must be done.

2)

Given data,

m = 10 g of KNO3

dissolved in V = 12.5 mL of H2O

D of water 1 g/mL

mass of water = 12.5 g of water

Solubility = mass/V

= 10/12.5

= 0.8 g of KNO3 per g of water

we want 100 g of water = 0.8*100

= 80 g of KNO3 / 100 g of H2O

About 47-48°C will become saturated solution