Lab Summaries: Ch 7: Solutions and Solubility
Exploration; How/why do some things dissolve? (Intro
to Solubility)

How can you tell if something is soluble or insoluble? (what happens for each?)

How can you tell when something has reached its maximum solubility? (what
happens?)

What factors decide whether something is soluble or insoluble? What factors
decide how soluble something is? Describe how.

Explain what is happening at the molecular level when something dissolves.

What are some factors that you think can affect how quickly a solute dissolves in
a solvent? Explain how.

What does it mean to be a polar molecule/compound? Give some examples.

Why is water called the universal solvent?

Explain why “likes dissolve likes” is true.
What effect does temperature of solvent have on solubility?

What does a solubility curve look like for a liquid solvent and a…
o Solid or liquid solute that is very soluble
o Solute that is a gas
o Solid or liquid that is insoluble

Draw and label the above lines on this graph:
Use the words saturated, unsaturated, supersaturated in the blanks below to
explain this lab. Words may be used once, more than once or not at all.
a. In this lab, you started by mixing KNO3
with water to make a solution that was
_____________________________. b. Then you heated
it up and dissolved the KNO3. That made the
solution _____________________________. c. Then you
cooled it down and took the temp right when
crystals started to form. If you did this right, at
that point the solution was
___________________________. d. Finally, you let it
continue to cool, which made it “snow” in the test
tube because the solution was
_____________________________ and the extra fell out
of solution. (precipitated)
Show those four letters from the story above (a, b,
c, d) on the graph
For the test, you should also be able to interpret solubility curves (Graph Reading: Solubility
Curves) and calculate concentrations and solubilities (Concentration and
Solubility Problems).
Lab Summaries: Ch 7: Solutions and Solubility
Exploration; How/why do some things dissolve? (Intro
to Solubility)

How can you tell if something is soluble or insoluble? (what happens for each?)
Soluble…it dissolves
Insoluble…it sinks to the bottom and does not
dissolve

How can you tell when something has reached its maximum solubility? (what
happens?)
No more dissolves, it sinks to the bottom

What factors decide whether something is soluble or insoluble? What factors
decide how soluble something is? Describe how.
The polarities of the solute and solvent …
like dissolves like

Explain what is happening at the molecular level when something dissolves.
Interactions between the molecules of solute
and solvent.

What are some factors that you think can affect how quickly a solute dissolves in
a solvent? Explain how.
Polarity…like dissolves like
Temperature…higher temperature, dissolve
faster
Pressure…higher pressure dissolve faster

What does it mean to be a polar molecule/compound? Give some examples.
Polar: electrons shared unevenly; molecule has
a partial charge. e.g. water, alcohol
Nonpolar: electrons shared evenly, no partial
charges. e.g. oil

Why is water called the universal solvent?
Many things can dissolve in it

Explain why “likes dissolve likes” is true.
Polar charges help pull apart polar molecules,
but not nonpolar
What effect does temperature of solvent have on solubility?

What does a solubility curve look like for a liquid solvent and a…
o Solid or liquid solute that is very soluble
Increases; goes up
o Solute that is a gas
Decreases; goes down
o Solid or liquid that is insoluble
Does not move (very much); flat line

Draw and label the above lines on this graph:
Solid or liquid
g per
100 g
H2O
gas
Insoluble or not very soluble
temperature
Use the words saturated, unsaturated,
supersaturated in the blanks below to explain
this lab. Words may be used once, more than once
or not at all.
a. In this lab, you started by mixing KNO3
with water to make a solution that was
saturated__. b. Then you heated it up
__
and dissolved the KNO3. That made the solution
unsaturated_. c. Then you cooled it
__
a, d
c
b
down and took the temp right when crystals
started to form. If you did this right, at that point
saturated_. d. Finally,
the solution was _
you let it continue to cool, which made it “snow” in
the test tube because the solution was
saturated_ and the extra fell out of solution. (precipitated)
_
Show those four letters from the story above (a, b, c, d) on the graph
For the test, you should also be able to interpret solubility curves (Graph Reading: Solubility
Curves) and calculate concentrations and solubilities (Concentration and
Solubility Problems).