C.2 (p.56) #1-3

6/26/13

1.
   a. The mass (grams) of potassium nitrate (KNO3) that will dissolve in 100g water at 60'C is 108g.
   b. The mass (grams) of potassium chloride that will dissolve in 100g water at 60'C is 44g.

2.
   a. 20g of potassium nitrate can be added to form a saturated solution at 30'C.
   b. 45g is the minimum mass of 30'C water needed to dissolved 25g potassium nitrate.

3.
   a. If the solution is agitated, than 90g of potassium nitrate will precipitate.
   b. To dissolve all of the KNO3, you would have to add 110 of the 55'C water.


ISCS (p.82) #1-8
1. Three teaspoons of sugar will completely dissolve in a serving of hot tea, and not dissolve in the equally sized serving of hot tea is because different temperatures can affect solubility. So and when temperatures are higher, the solute dissolves more easily.

2. The maximum mass of potassium chloride that will dissolve is 48g.

3.
   a. 100.0 mL water: 200 grams
   b. 355 mL water: 710 grams
   c. 946 mL water: 1,892 grams

4.
   a. NaCl, KCl, KNO3
   b. KNO3, KCl, NaCl

5. Saturated is when a solvent has dissolved as much solute as it can retain at a specific temperature, and therefore the solute settles at the bottom of the container; even stirring the mixture will not make the crystals dissolve. Unsaturated is a solution that contains less dissolved solute than the amount that the solvent can normally hold at a specific temperature.

6. Solutibility of potassium nitrate (KNO3)
  a. 30 grams
  b. Supersaturated
  c. 90 grams

7.
  a. Unsaturated: the crystal will dissolve, therefore possibly making the solution saturated
  b. Saturated: the crystal will settle to the bottom as a precipitate because the solvent has already dissolved as much solute as it can.
  c. Supersaturated: the crystal will settle to the bottom of the container as a precipitate, and by doing this it will add on to the precipitate that was already there.

8. The percent concentration of ethanol, expressed as percent ethanol by mass is 1.15 x 35 = 40.25%.