UNIT 2 – MATTER AND CHEMICAL CHANGE

TOPIC 1 – EXPLORING MATTER

Learning Target:Classify material based on composition and properties (pure substances and mixtures).

•Chemistry is the:•The study of matter

• The properties (differences) between matter

• Changes in matter (reactions)

But what is matter?

• Matter is anything that: Has massTakes up space

What exists on Earth but is not matter?

Energy!!

All chemicals need to be treated with care.

• Many chemical are CAUSTIC and will, burn, corrode, or destroy organic tissue.

Eg. Acids, strong bases, and other chemicals easily break down skin and muscle and can cause permanent damage.

WHMIS SHEET

Fill in the WHMIS Info sheet using page 447 in your text and/or Google

Classifying MatterMatter is most often described using

the Particle Model of Matter1. All matter is made up of tiny particles.

Eg. In one drop of water there are 1 700 000 000 000 000 000 000 water particles in it!(that’s 17 with 20 zero’s behind it)

The number of particles in the human body is approximately equal to the number of peas it would take to cover 250 000 Earths to a dept of 1.5 meters!

If every person on the planet counted continuously from birth to death and we added these numbers together, that would be about how many atoms that make up the head of a

pin!

2. Each pure substance has its own kind of particles that are unique.

The particles of one type are all identical to each other and are different from other particles of other pure substance.

Eg. All salt particles taste salty. All sugar particles taste sweet. All water particles have the same melting (0 0c) and boiling point (100 0c).

3. Particles attract each other.Objects with stronger attraction between their particles are solids. Objects that have weak attraction between particles are gases.

4. Particles are always moving.Vibrating, rotating , bumping into each other.

Faster moving particles take up more space as they bump into each other causing the object to expand. As the temperature decreases, the particles get tighter together and the object contracts.

5. As the temperature increases, the particles move faster (expand). If the temperature decreases, the particles move slower (contract).

The particle model helps to explain the 3 states of matter:

GAS LIQUID SOLIDAttraction between

the particles. Very Weak. Weak. Strong.Distance between the

particles. Far. Tight but can easily move past one another. Tight.

Shape Fills the container. Takes the shape of its container.

Has a fixed shape.

Compressible? Yes. No. No.

Matter can be further classified according to its composition.

MatterSolid, Liquid, or Gas

Pure Substances Mixtures•Only one type of particle

•Have set properties (values DO NOT change)

Eg. Water (H2O) – always boils at 100oc

Eg . Salt (NaCl) – always boils at 1465oc

•Two or more types of particles mixed together

•Values of properties change depending on how much of each particles is present in the mixture

Eg. Salt Water – boiling point varies depending on the amount of salt in the solution (the more salt, the higher the boiling point)

Mixtures can further be broken down:

HETEROGENEOUS (Mechanical Mixtures)

HOMOGENEOUS (Solutions)

• Mixtures

-particles are evenly mixed so it looks like ONE substance (uniformly mixed)-clear (can be colored) and will not filter out-light passes through evenly

Eg. Sugar water

-have varying sizes of particles in the mixture (can be seen)

-can be further classified as:

•Ordinary Mech. Mix.

•Suspensions

•Colloids

Heterogeneous Mixtures HETEROGENEOUS (Mechanical Mixtures)

Ordinary Mech. Mix. Suspensions Colloids-can see the different parts-parts stay mixed

Eg. cookie dough gravel, cement

-looks like one substance but the two parts will separate out over time

Eg. Dust and water

-CAN be filtered and WILL scatter light

-small particles of one substance suspended in another -WILL scatter light

Eg. Hair Gel, Fog (Water vapour and air)

Solution -light easily passes though

Colloid -light is scattered by the particles in the liquid

Colloids

Emulsions-a liquid that is mixed in with another liquid

PROBLEM: may quickly separate to form layer of the original liquids. That is why we use emulsifying agents, such as eggs.

Eg. Milk, jelly, and salad dressing

HomeworkPage 983,4,5