Solubility Curve Interpretation #1

Name:______Date:______Period:______

Solubility Curve Interpretation #1

1.What relationship exists between solubility and temperature for most of the substances shown?

2. What is the exception?

3. What explains why solids become more soluble as temperature increases and why gases become less soluble? Use the following words to help justify your response: temperature, collisions and energy.

4. Which is more soluble NaNO3 or KCl? Does the temperature matter? Why or why not?

5. How does the line drawn for a particular substance relate to the saturation of a solution of thatsubstance? Use the following words to help justify your response: saturated, unsaturated,supersaturated.

6. How many grams of NH4Cl will dissolve in 100. grams of water at 90.0C?

7. How many grams of KClO3 will dissolve in 300. grams of water at 30.0C?

8. How would you make a saturated solution of KNO3 at 60.0C in 50. grams of water?

9. If you were asked to make a saturated solution of KCl in 100. grams of water, what other piece of

information would you need to before you could start? Why?

10. If you start with a saturated solution of NH3 in 100. grams of water at 10.0C, how many grams of NH3

gas would bubble out of solution if you raise the temperature to 80.0C?

11. A saturated solution of NaNO3 was made with 300. grams of water at 40.0C. How much NaNO3

could be recovered by evaporating the solution to dryness?

12. A saturated solution KNO3 in 400. grams of water at 50.0C is cooled to 10.0C. How much KNO3 will

come out of solution as crystals?

13. You start with 200. grams of ice saturated with SO2 at 0.0C. How many grams of SO2 will bubble outof solution if you melt the ice and raise the temperature of the water to 80.0C?

KEY

Directions: Answer in complete sentences and show all work for calculations.

1. What relationship exists between solubility and temperature for most of the substances shown?

A direct relationship is shown for most substances, as temperature increases thesolubility of most substances increases.

2. What is the exception?

The exception is gas solubility. Gases are less soluble at higher temperature,illustrating an indirect relationship

3. What explains why solids become more soluble as temperature increases and why gases becomeless soluble? Use the following words to help justify your response: temperature, collisions andenergy.

As temperature increases both speed of the water molecules and the number ofcollisions increase. A solid remains dissolved by the continual motion of the eatermolecules. The more energy and motion, the more particles that can remain insolution. This is especially true for ionic compounds, because water is polar and theopposite charges help stick the water molecules to the ions. Gases are often nonpolarand they have very low boiling points, so as temperature increases they tend to “boilaway”. That is why a soda will go flat much faster if it is left in a warm place.

4. Which is more soluble NaNO3 or KCl? Does the temperature matter? Why or why not?

NaNO3 because the higher line indicates that more NaNO3 can be dissolved at ALLtemperatures.

The line marks the saturation point of a solute in 100 grams of water. If you have lessgrams dissolved than indicated by the line then your solution is unsaturated at thattemperature. If you have more, then your solution is supersaturated at thattemperature.

6. How many grams of NH4Cl will dissolve in 100. grams of water at 90.0C? 72 grams

7. How many grams of KClO3 will dissolve in 300. grams of water at 30.0C?

300. g of H2O X 10. g KClO3 = 30. g KClO3

100. g H2O

8. How would you make a saturated solution of KNO3 at 60.0C in 50. grams of water?

The graph indicates that that 106 grams of KNO3 will dissolve in 100. grams of water,

so I need only 106g /2= 53 grams of KNO3 to make the solution. So I would measure

out 50 grams of water and 53 grams of KNO3 and mix them together to make the

solution.

9. If you were asked to make a saturated solution of KCl in 100. grams of water, what other piece of

information would you need to before you could start? Why?

You would need to know the temperature of the solution. The saturation point is very

different depending on the temperature

10. If you start with a saturated solution of NH3 in 100. grams of water at 10.0C, how many grams of NH3gas would bubble out of solution if you raise the temperature to 80.0C?

100. grams of water at 10.0C can hold 70. grams of NH3.

100. grams of water at 80.0C can hold 14 grams of NH3.

So 70. g -14 g = 56 grams of NH3 will bubble out.

11. A saturated solution of NaNO3 was made with 300. grams of water at 40.0C. How much NaNO3could be recovered by evaporating the solution to dryness?

So 300. grams of water can hold 3 X 106 g = 318 g NaNO3 will be recovered.

12. A saturated solution KNO3 in 400. grams of water at 50.0C is cooled to 10.0C. How much KNO3 willcome out of solution as crystals?

From the graph 100. grams of water at 50.0C can hold 83 g of KNO3

So 400. grams of water can hold 4 X 83 g = 332 g KNO3

From the graph 100. grams of water at 10.0C can hold 21 g of KNO3

So 400. grams of water can hold 4 X 21 g = 84 g KNO3

As the solution is cooled 332 g- 84g = 248 g KNO3 will form crystals.

13. You start with 200. grams of ice saturated with SO2 at 0.0C. How many grams of SO2 will bubble out of solution if you melt the ice and raise the temperature of the water to 80.0C?

From the graph 100.g of ice at 0.0C can hold 23 g of SO2

So 200. grams of ice can hold 2 X 24 g = 48 g SO2

From the graph 100g. of water at 80.0C can hold 4 g of SO2

So 200. grams of water can hold 2 X 4g = 8 g of SO2

As the solution is heated 48 g – 8 g = 40 g of SO2 will bubble out.