Solubility of Salts
Objective
When we cook pasta, we frequently dissolve table salt in water. Is there a limit to how much
salt we can get into the water? When ionic-bonded compounds (like table salt, NaCl) are
dissolved in polar solvents (like water), the polar water molecules act to pull the ions in the
compound apart. When this happens (called dissociation), ions are released into the solution.
Is there a limit to the number of ions that can exist in solution?
http://phet.colorado.edu/
Directions
PART 1: Observation of Salt and Water Interaction
Play with the Sims  Chemistry  Salts & Solubility
If a yellow bar drops down in your browser, click on it and select "Allow
1. Click on the “Table Salt” tab
.
Blocked Content"
2. Begin by shaking salt shaker a few times. Make
at least 2 observations of salt as it enters the
water.
Given the Structure for Water and IONic Salt Below…
Why is Water Able To Dissolve IONic Salts?
It is able to dissolve salts because the sodium and
chloride ions break apart and are able to dissolve when
there is enough water.
PART 2: Solubility Limit?
3. Reset the application and investigate if there is a point at which solute
can no longer dissolve (called Saturated Point). Record the amount of
ions dissolved and the Original volume of solvent used.
4. Remove ½ of the solvent from the original amount. Investigate the
saturation point at this amount of solvent. Record the amount of ions
dissolved and the volume of solvent used.
5. Add ½ more solvent to the original amount. Investigate the saturation
point at this amount of solvent used. Record the amount of ions
dissolved and the volume of solvent used.
How Does the Amount of Solvent Affect Solubility?
When there isn't enough solvent then the solubility
increases because the ions are not be able to dissolve.
Maximum amount
of ions dissolved
Na+
ClNa+
Cl
-
Na+
Cl-
181
181
92
92
Volume at
Saturation Point
5.0 x 10 ^-23 L
104
104
2.5 x 10^-23
L
5.0 x 10^-23
L
PART 3: Can Solubility Change With Other Solutes
1. Click on the “Slightly Soluble Salts” tab.
2. Start with any solute and investigate the saturation point using the given amount of solvent. Write the formula for the
solute and record the amount of ions dissolved and the volume of solvent used.
3. RESET the application and repeat step 2 for two more different solutes.
Solubility of Different Solutes
Name Strontium Phosphate
Name
Name
Silver Bromide
Sr 45
PO 30
1.00
L
Formula
AgBr
Ag 44
Br 44
1.00
L
Dissolved
ions
Formula
Sr3(PO4) 2
Dissolved
ions
Dissolved
ions
Formula
Silver Arsenate
Ag3AsO4
Ag 252
AsO 82
1.00
L
What you learned about the saturation points of salts.
I learned that saturation points of salts is when there is not enough water where the salt can no
longer be dissolved and doesn't break apart and stays at the bottom of the solution.
Conclusion Questions:
2. Identify two components of a solution. Explain each component.
(2pts)
A solute and a solvent
1. Using your book or internet for reference,
define the following words: (3pts)
Saturated Solution
Solution that contains the maximum
amount of solute that is capable of being
dissolved.
3. Evaluate the statement below. Please explain your answer. (1pt)
“All mixtures form solutions.”
Not all mixtures are solutions. A solution is a specific
term that describes a mixture of a solute and it
dissolves. Such as oil and water is not dissolved so
that isn't a solution.
4. Explain why water by itself is not a solution. (1pt)
Water is not a solution because nothing is being
mixed with it so there isn't a different outcome.
Unsaturated Solution
A solution that contains less than. the
maximum amount of solute that is capable
of being dissolved.
Solubility
The ability to be dissolved, especially in
water.
5. How do you know that a solution has reached its saturation
point? (1pt)
When any additional amount of the substance that is added simply remains as a salad [recipitate or
is released as a gas.
6. What did you notice when you added extra solvent (water) to a saturated solution? (1pt)
Then it starts to dissolve again and there are no more bonds.
7. If an UNsaturated solution of salt and water is evaporated. What would you expect to see/happen? (1pt)
Then the solutions will turn into gasses .