1. 6.4 – NOTES Solutions, Suspensions, and Colloids

2. B.1 Physical Properties of Water
The Earth is unique because it has so much water.
70+% of Earth's surface is covered with oceans of an average depth of 3 km
Matter
Anything that has mass and takes up space

3. Physical property
Properties of the senses – can be observed without changing the make- up of the substance
Density
The measure of mass in a given volume
The formula for density is D = M V
The density of water at 25 0C is g/ml

4. Freezing point of water is
An unusual property of water is that solid water is less dense than liquid water
Aqueous solutions- solutions that are dissolved in water
NH3 (aq)  shows its aqueous solution
Pure water is clear, colorless, odorless, and tasteless, which are physical properties

5. B2. Density
Practice Problem: In the foul water lab, you observed that coffee grounds settled to the bottom of the water sample, whereas oil floated on top. Explain this observation in terms of the relative densities of coffee grounds, water and oil.
Highest Density  Coffee Grounds  Water  Oil  Less Dense

7. Mixture
Two or more things mixed together that can be separated without losing individual properties
These can be separated by physical means, without a chemical reaction

8. Heterogeneous mixture
Composition is not uniform throughout
Ex. Muddy water
Suspension
Particles are large enough to see and settle
to the bottom, can filter

9. Colloid
Particles are small enough to stay suspended in liquid and small enough to not see, can’t filter
Milk is a colloid
Other Examples; Jello, Glue
Dissolving
A process when crystals separate into particles so small they cannot be seen at high magnifications
In a heterogeneous mixture, the particles are large enough to reflect light

10. Homogeneous mixture
Composition is uniform throughout
Solutions
The only type of homogeneous mixture
The particles in a solution are small enough that they cannot reflect light and cannot be filtered
Solutions are made of two parts
Solute – what gets dissolved
Solid – Salt in water
Liquid – Alcohol in water
Gas – Carbon dioxide in water
Solvent – what does the dissolving, usually liquid or gas

12. Solutions and colloids look very similar- you cannot see particles in them.
The only way to tell the difference is to perform the Tyndall Test
Positive Tyndall Test Negative Tyndall Test