Is there a limit to the amount of salt that can dissolve in a given amount of water?

1. Focus Question: What happens if
you keep adding salt to water?
Investigation 2-1
Mixtures and Solutions

2. What is a Solution?
• How would you test a mixture to find out
if it is a solution?
• We made a salt solution by dissolving a
spoon of salt in 50 ml of water. What do
you think would happen if we put two
spoons of salt in 50 ml of water?
• Would it dissolve to make a solution?
• How about three spoons?
• Will salt keep dissolving forever?

3. Investigation Question
• How can we find out what might happen
if you keep adding salt to 50 ml of
water?

4. Available Materials
• Bottle - keep solution from spilling
• Funnel - use to direct salt into the bottle
• Sticky note - mark the water level at the
beginning
• Syringe
• Water
• Salt
• Measuring scoop

5. Challenge
• Question: “How much salt can you
dissolve in 50 ml of water?”
How much water will you put in the bottle
at the start?
How much water will you add later?
Why would you not add any water later?

6. Getting Started
• Put 50 ml of water into your bottle
• Put a sticky note to mark the beginning
water level
• Add one spoon of salt to bottle. Shake
the bottle until the salt dissolves.
• Add another spoon of salt.
• Repeat above until salt stops dissolving
• Keep track of the spoons of salt added

7. Review
• What happened to the salt when you
put it in the water?
• Where is the salt now?
• What happened to the level of the
liquid?
• Why did the level go up?

8. Saturation
• You made a solution by dissolving solid
material in a liquid. When solid material
is added to a solution until no more will
dissolve, the solution is a saturated
solution. You all made saturated salt
solutions.
• How do you know you have a saturated
salt solution?

9. How much salt dissolved?
• You have a saturated solution. How
much salt did it take to saturate 50 ml of
water?
• More precise: How many grams of salt
are dissolved in your saturated salt
solution?
• Is the undissolved salt at the bottom of
the bottle part of the saturated solution?
• What is the mass of 50 ml of water?

10. Plan - Worksheet
• Place labeled cup under the funnel
• Filter the solution using a wet filter paper.
Saturated solution will pass through the filter; the
undissolved salt won’t
• Place saturated salt solution on one side of the
balance and 50 ml of plain water on the other side
• Add gram weights to the plain water to achieve
balance. The mass added to the 50 ml of water is
equal to the mass of salt dissolved into the 50 ml of
water used to make the saturated solution
• Record the number of grams of salt it takes to
saturate 50 ml of water on your worksheet.

11. • A salt solution is made of two parts: the
water and the salt. These two parts of a
solution are called the solvent and the
solute.
• The solvent is the liquid into which the
solid material goes. The solute is the
material that dissolves.
• A solution is always made of a solvent
with some kind of solute dissolved in it.

12. Vocabulary
• Solvent
– The liquid part of a solution
• Solute
– The solid that dissolves in the solvent (liquid)
• Saturated Solution
– A solution in which no more solute will dissolve in
the solvent

13. Content
• Is there a limit to the amount of salt that
will dissolve in water?
• How can you determine the amount of
salt present in a saturated volume of
water?
• Your questions?
Homework: Read Solutions Up Close, pg
16-19 and answer questions