1. 8.2 Solubility and Concentration
Key Concepts
How are solutions with different amounts of solute described?
What factors determine the solubility of a solute?
What are three ways to measure the concentration of a solution?

2. Solubility
maximum
The _______________ amount of solute that dissolves in a given amount of solvent at a constant temperature is called _______________
Solubilities are usually expressed
in _______ of solute per
100 grams of ____________
solubility
grams
solvent

3. Which compound is the most soluble in water at 20°C
At a given temperature, different substances have different solubilities in water.
Which compound is the most soluble in water at 20°C
Table sugar

4. Unsaturated Versus Saturated
If the amount of solute dissolved is _______ than the maximum that could be dissolved, the solution is called an ______________ solution
Ex: Earth’s oceans contain _______ dissolved salt than they can hold
less
unsaturated
less

5. maximum
A solution that holds the ____________ amount of solute per amount of solution under the given conditions is called a ______________ solution
Ex: The Dea Sea has a salinity of ______ salt compared to only about ______ percent for ocean water
_______________ solutions contain ________ solute than the usual maximum amount and are typically _____________
Ex: While making fudge, you heat a highly
concentrated mixture of sugar, chocolate
and a water-based solvent to a
_________ enough temperature to make a __________ solution that is supersaturated
saturated
25%
3.5
more
Supersaturated
unstable
high
sugar

6. Like Dissolves Like
Water can dissolve an enormous variety of substances, but it does ______ dissolve everything
The phrase that scientists often use when predicting solubility is _____________________
This phrase means that dissolving occurs anytime a solute and solvent have ______________ in polarity
NOT
“like dissolves like”
similarities

7. Practice Solubility Questions!
Can water dissolve other polar molecules?
Can water dissolve other compounds that are similar to it in structure and hydrogen bonding?
Can water dissolve a nonpolar molecule like oil?
Can oil dissolve other nonpolar molecules?
Yes…both are polar
Yes…similar structure and bonding
No…not similar or “unlike”
Yes….both are nonpolar

8. Special Topic: Soap Soap has unique properties
because one end of the molecule
is ____________ and the other
end is _____________
The polar end attracts ____________ and the nonpolar end attracts ___________
Basically, the nonpolar end ____________ the oil and the polar end interacts with water to ____________ the oil away
polar
nonpolar
water
oil
dissolves
rinse

9. Effect of Temperature on Solubility
The solubility of most __________ solutes _____________ with an increase in temperature
What is being plotted on the x-axis?
What is being plotted on the y-axis?
solid
increase
temperature
Grams of solute

10. 83 g 112 g supersaturated unsaturated
At 20°C, how many grams ofNaNO3 are dissolved?
At 50°C, how many grams ofNaNO3 are dissolved?
If 130 grams of NaNO3 were dissolved at 50°C, what kind of solution would it be?
If 80 grams of NaNO3 were dissolved at 50°C, what kind of solution would it be?
83 g
112 g
supersaturated
unsaturated

11. Solubility of Gases
The solubility of a _________ in a liquid actually ______________ with increases in temperature
Due to this many fish must live in _______ water so that the concentration of dissolved ____________ remains high
Think of soda in a bottle…does it taste
more carbonated (bubbly) when it is cold
or hot?
gas
decreases
cold
oxygen
Cold…contains more CO2

12. Pressure also affects the solubility of a gas…
Increasing pressure allows ________ carbon dioxide to dissolve in a liquid
Think of soda in a bottle again…is it more carbonated with or without the cap on?
more
With the cap…more pressure

13. Molarity
Suppose you are hospital or pharmacy worker, and you need to make a salt solution that matches the salt concentration of a _____________ blood
patient’s
Blood is a ___________
solution, but this term gives only
__________________ information
You will need to measure things
accurately using numbers or
_________________ information
dilute
qualitative
quantitative

14. Concentration units can ________ greatly.
For chemistry applications, the concentration term ____________ is generally the most useful
Molarity, symbolized with an ______, is defined as the number of _________ of solute per __________ of solution
Molarity = _moles of solute_
liter of solution
Notice that the ______________ in liters is the total volume for the _____________
vary
molarity M
moles
liter
volume
solution

15. Concentration can also be expressed as percent by _____________
Example: Fruit juice labels
What percentage of cranberrry
juice is found in the product
shown?
volume
27%

16. Concentration of Solutions
Percent by Mass
Concentration expressed as a percent by ___________ is more useful when the solute is a solid.
mass

17. Review Question 1
Explain the difference between an unsaturated, saturated, and supersaturated solution
Contains the
max. amount
of dissolved solute
Contains less
than the max.
amount of dissolved
solute
Contains more
than the max.
amount of dissolved
solute

18. Review Question 2
How does temperature affect solubility for most solid solutes?
And for gases dissolved in a liquid?
As temp. increases, so does solubility
As temp. increases, solubility decreases

19. Review Question 3 What is the equation for molarity?
M = _moles of solute_
liter of solution