Grade 9 Science– Notre Dame College School

John Dalton – the guy who came up with particle theory

Agenda What is matter

The Particle Theory

Mixtures vs. Pure Substances

Mixtures Heterogeneous Mixtures

Solution

Homogeneous Mixtures Mechanical Mixture

Suspension

Solution

Pure Substances Elements

Compounds

What is Matter? Matter is anything that contains mass & volume (takes

up space)

Energy, such as light, heat, and sound, is NOT matter

IT ALL MATTERS!

The Particle Theory of Matter This provides a way to describe the structure and

behaviour of matter.

There are 4 principals of the particle theory written by a chemist named John Dalton.

Think About it! Look at a piece of chalk If you broke a piece

of chalk in half, would it still look like and behave like chalk?

How small of pieces would you have to break a piece of chalk so that it isn’t chalk anymore – is that even possible?

The answer is YES, because the smallest pieces of chalk are made up of particles and the particle theory explains how this works!

The Particle Theory of Matter 1. All matter is made up of very tiny objects

called particles.

These particles are VERY tiny – too small to be seen with any regular light microscope

The Particle Theory of Matter 2. All Particles have

spaces between them.

The size of these spaces determine the state of the matter

The Particle Theory of Matter 3. Particles present in matter are always in motion.

In a solid, they vibrate together

In a liquid, they stay close together but slide along each other

In a gas, they bounce and move in all directions!

The Particle Theory of Matter 4. The particles in a substance attract each other.

The degree that particles are attracted to each other is different in difference substances,

Take a guess!

Which substance do you think has the strongest attractions? Which has the weakest?

Iron

Water

Oxygen

http://www.youtube.com/watch?v=I9xB4hhWvXY

Recap: Here they are all again

1. All matter is made up of very tiny objects called particles.

2. All particles have spaces between them.

3. Particles present in matter are always in motion.

4. The particles in a substance attract each other.

Pure Substances vs. Mixtures All matter can be divided into two big categories:

PURE SUBSTANCES and MIXTURES.

Pure substances are made up of one type of element or compound

Mixtures are a combination of pure substances (2 or more types of particles)

Versus

Pure Substances Pure substances are made up of only ONE type of

particle or matter, and has a unique set of properties.

Pure substances are in the form of either elements or compounds.

Elements Element- a substance that cannot be

broken down into any simpler substance by chemical means.

They are only made up of one type of atom (one type of particle)

Examples are Oxygen, Calcium, Iron, Carbon and Helium (see periodic table)

Compounds

Water is a molecule because it is made out of two types of atoms (oxygen and hydrogen)

Oxygen

Hydrogen

Hydrogen

Water is a compound because it has many molecules of one type (H2O = Water)

A compound is a pure substance that is made from two or more elements that are combined together chemically.

Compounds are made up of many molecules that are held together by chemical bonds!

Mixtures A mixture is a combination of two or more different

pure substances (different types of particles). They do not chemically combine.

Mixtures can be divided into 2 big categories:

Heterogeneous Mixtures (Mechanical)

Homogeneous Mixtures (Solutions)

Heterogeneous Mixtures Made up of two or more particles

where the different particles are easy to see and separate.

Can be divided into two categories:

Mechanical mixtures

Suspensions

An Oreo cookie is a heterogeneous mixture

Mechanical Mixtures the different substances that make up the mixture are

visible.

Made up of several distinct parts

A lasagne, parfait, and a cookie are both examples of

mechanical mixtures

THINK ABOUT IT! What are some of the

parts of these mechanical mixtures?

Suspensions A cloudy mixture where small

particles of one substance are held (float) in another substance

These particles can be separated by filtration.

Salad Dressing, glittery nail polish,

and yogurt are examples of suspensions

Homogeneous Mixtures A homogenous mixture

occurs when 2 or more particles dissolve in one another.

Only one layer of phase is visible.

Solutions are homogeneous mixtures!

Solutions A mixture of 2 or more

substances that dissolve in each other. Only one layer or phase can be seen.

Kool-Aid and tea are solutions because you cannot see the sugar crystals floating in the Kool-Aid, and you cannot see the tea floating in the tea when the bag is removed Kool-Aid and tea

are examples of solutions

Atom

The smallest particle of an element is the atom

Elements - molecule

2

2 atoms of hydrogen bonded together

Compound - Molecule

2 or more different types of atoms bonded

together. Many molecules make a

compound

Which Is It? (element, compound

or mixture)

ELEMENT

Which Is It?

COMPOUND

Which Is It?

MIXTURE