Pure Substances and Mixtures

Matter is anything that takes up space and has mass.

The main states of matter are Solids, Liquids and Gases.

• Most substances fit into at least one of the solid, liquid or gas categories.

• What happens when one doesn’t fit?

What am I?

Non-Newtonian Fluid

• Quicksand is a non-newtonian fluid.– When undisturbed is appears to be a

solid, but a minor (less than 1%!) change in the stress on the quicksand will cause a sudden decrease in it’s viscosity.

• http://www.youtube.com/watch?v=MJTGwZM05lQ

What About Shaving Cream?

Matter can be divided into mixtures and pure substances:

A mixture contains two or more different kinds of particles.

A pure substance only contains one type of particle.

MATTER

Mixtures Pure Substances

Mechanical Mixtures Solutions

Compounds Elements

Physical Change

Chemical Change

Pure Substance

Pure Substance

Mixture

Mixtures can be heterogeneous or homogeneous:

Heterogeneous mixtures have particles that are not uniformly

scattered (you are able to see the different types of particles).

Homogeneous mixtures have particles that are uniformly scattered (you can

only see one type of particle).

Heterogeneous mixtures are also called mechanical mixtures.

Homogeneous mixtures are called solutions.

Questions1. Which of the following is a mechanical mixture? Explain

Wood, Tap water, Orange Juice, Loonie

2. State the reason and whether each of the following is a mechanical mixture or a solution.

Hotdog relish, Freshly squeezed grape fruit juice, soda water, Apple juice, Granola, Vegetable soup.

Heterogeneous Mixtures

• “Heterogeneous” means different kinds.

• In many mixtures, like granola, you can clearly see separate pieces in the mixture.

• If you take a small sample from such a mixture each sample may have different properties from another sample.

Homogeneous Mixtures

• “Homogeneous” means the same kind.

• In these mixtures the particles of pure substances mix together so completely that the mixture looks and feels like it is only made of one kind of particle.

• Every sample of this mixture will be the same.

Solutions

• In solutions one substance has mixed completely, or dissolved, into the other.

Solutes and Solvents

• The substances that dissolves are called solutes.

• The substances that do the dissolving are called the solvents.

• In sugar water, the sugar is the solute and the water is the solvent.

The Particle Theory of Matter

Scientists use the particle theory of matter to explain what matter is.

Democritus

The particle theory of matter consists of 4 principles:

1. All matter is made up of tiny particles.

2. One substance is made up of all the same particles and different substances are made of different particles.

3. Particles are always moving; the more energy the particles have, the faster they move.

4. There are attractive forces between two particles. These forces are stronger when the particles are closer together.

Particle Theory Questions1. State what happens to the distance between particles when a substance changes

            a. from a solid to a gas

            b. from a liquid to a solid  

2. Why is it easier to compress a gas than a liquid?

3. What causes a solid to have a definite shape and volume?

4. Gas particles are considered to have very little attraction for one another. Explain.

5. Why is a solid iron more dense than liquid iron?      

 6. Explain why solids, liquids and gases expand when heated. Use the particle theory.

 7. Use the particle theory to explain why:

           a. Gases have low density.

           b. It is easier to move your hand through air than through water.

 8. Explain in terms of the particle theory, what happens when:

       a. A liquid freezes into a solid

       b. A vapour condenses into a liquid.

9. In which type of matter: solids, liquids or gases are the particles further apart?