SOLUTIONS

What is a solution?

A well-mixed mixture that contains a solvent and a solute.

The solvent is the largest amount of the mixture, usually liquid, but not always.

The solute is the substance dissolved by the solvent.

Which of the following is the solvent in the solution of sugar and water?

sugar

water

oxygen

Which is the solvent in a solution of soda pop?

Carbon dioxide

water

sugar

Water is the universal solvent!

Yes

No

Can you see through a solution?

Colloids

Mixtures containing small, undissolved particles that do not settle out. Milk will not separate (unless its spoiled

– ewww) Colloids have larger particles than

solutions.

Other examples – shaving cream, fog, mayonnaise

Suspensions

A mixture in which particles can be seen and easily separated by settling or filtration.

Examples: snow globe, sand in water, dust in air, paint

Ionic Solutions

Remember from last unit that ionic compounds in solution can conduct electricity. ex: salt in water can transmit a current

Review: What is an ionic compound?

2 or more non-metal atoms bonded together

2 or more metal atoms bonded together

1 metal and 1 non-metal atoms bonded together

Hydrogen bond

Yes

No

Is table sugar (C12H22O11) an ionic compound?

What happens to solvents when a solute is added?

-Freezing point lowered (think road salt)

Meaning that ice will melt at colder temperatures

-Boiling point increased (add to pot of water for noodles)

Does salt water have a lower or higher freezing point than pure water?

Higher

Lower

If you mix food coloring with water and make it green colored, what did you

make?

solution

suspension

colloid

Concentration

The amount of solute in a solvent You can change the concentration of

a solution by adding or removing solvent of solute.

Dilute solution

Mixture that has only a little solute dissolved in a certain amount of solvent.

Concentrated Solution

Has a lot of solute compared to the amount of solvent.

Scenario: You just made Kool Aid but it is too sweet. What can you do to make it taste less sweet?

Add more water

Add more sugar

When you add more water, you are making the solution more dilute. You are decreasing the concentration of sugar in the solution by adding more water.

Which part of the Kool Aid is the solute?

sugar

water

Practice Calculating Concentration

Concentration = Amount of solute x 100

Amount of solution

Practice problem: A solution contains 12 grams of sugar dissolved in 36 grams of solution. What is the sugar concentration of the solution?

Answer: 33%Did you get that?12 ÷ 36 = 0.33 x 100 = 33%

The solution has a sugar concentration of 33%

Solubility

How much solute can be dissolved in a solvent at a given temperature.

When you’ve added so much solute that no more will go into solution, it is called a saturated solution.

If you can continue to add more solute, you have an unsaturated solution.

We can use solubility to find an unknown substance because solubility is a characteristic property of matter.

See page 96 in textbook – temperature and solubility analyzing data.

supersaturated

unsaturated

saturated

What factors can affect solubility?

Pressure, time, type of solvent

Pressure, type of solvent, temperature

Pressure, concentration, humidity