Solubility Curve Practice Problems Worksheet

You'll notice that for most substances, solubility increases as temperature increases. As discussed earlier in solutions involving liquids and solids typically more solute can be dissolved at higher temperatures. Can you find any exceptions on the graph?

Here's an example of how to read the graph. Find the curve for KClO3. 

At 30°C approximately 10g of KClO3 will dissolve in 100g of water. If the temperature is increased to 80°C, approximately ​ (a)   of the substance will dissolve in 100g (or 100mL) of water.

• 40 g
• 5 g
• 25 g
• 60 g

Directions:  Use the graph to answer the following questions.  REMEMBER UNITS!

1. What mass of solute will dissolve in 100mL of water at the following temperatures? 

   1. KNO3 at 70°C = ​ (a)  

   2.  NaCl at 100°C=​ (b)  

   3. NH4Cl at 90°C=​ (c)  

Which of the above three substances is most soluble in water at 15°C. = ​ ​ (d)  

• 130 g
• 40 g
• 70 g
• NaCl
• 50 g, 20 g, 10 g, KNO3
• 200 g, 60 g, 90 g, NH4Cl
• 10 g, 5 g, 15 g, NaCl

1. Which substance on the graph is a gas?​ ​ (a)   and ​ (b)  

• NH3
• Ce2(SO4)3
• H2O
• NaCl
• C6H12O6

1. Types of Solutions

On a solubility curve, the lines indicate the concentration of a ​ (a)   solution - the maximum amount of solute that will dissolve at that specific temperature.

Values on the graph ​ (b)   a curve represent unsaturated solutions - more solute could be dissolved at that temperature.

• saturated
• under
• over, concentrated
• dilute, saturated
• supersaturated, under

Label the following solutions as saturated or unsaturated.

If unsaturated, write how much more solute can be dissolved in the solution

Groups:

(a) a solution that contains 70g of NaNO3 a

,

(b) a solution that contains 50g of NH4Cl at

,

(c) a solution that contains 20g of KClO3 at

,

(d) a solution that contains 70g of KI at 0°

• saturate

• 25 g

• saturated

• 60 g

• unsaturate

• unsaturated

 a.  What is the solubility of KCl at 5°C?  ​ (a)  

    b.  What is the solubility of KCl at 25°C?  ​ (b)  

c.  What is the solubility of Ce2(SO4)3 at 10°C?  ​ (c)  

d.  What is the solubility of Ce2(SO4)3 at 50°C?  ​ (d)  

• 28 g
• 33 g
• 12 g
• 5 g
• 50 g
• 15 g
• 1 g

a.  At 90°C, you dissolved 10 g of KCl in 100. g of water.  Is this solution saturated or unsaturated?

b.  How do you know?

3. A mass of 100 g of NaNO3 is dissolved in 100 g of water at 80ºC.  

a) Is the solution saturated or unsaturated?______________________________

b) As the solution is cooled, at what temperature should solid first appear in the solution? Explain.