Introduction to MatterPages 6-15 “K”

Matter is anything that has mass and takes up space

• Everything around us is matter.• You and I are matter too!

• Yes—it is true.

What are the properties of matter?

• Rough• Gray• Small• Sharp• Brown• Hollow• Hard

Properties describe . . . . . . .

• You could add gas, liquid, solid, hot, cold, soft, and the list goes on and on and on and on.

• Every form of matter has two kinds of properties—physical properties and chemical properties.

Chemistry is the study of the properties of matter and how matter changes.

• Matter will change depending on its makeup.• Example: Lets look at oxygen. A physical

property is that it is a gas at room temperature.

• A chemical property of oxygen is that it reacts with iron to from rust.

Physical property/physical change

• When dealing with physical properties, or change, the properties of the pure substance can be observed without changing it into another substance.

• Example:

Substance

• Is a single kind of matter that is pure. It has a specific set of properties and makeup.

• The following example has definite physical properties and also definite chemical makeup properties:

The example:

• Table salt. It has the same physical and chemical properties whether it comes from seawater or a salt mine. It is always 39.3% sodium chloride and 60.7% chlorine by mass.

What about the batter for blueberry muffins?

• What does it have in it?• Blueberries, flour, salt, sugar, eggs, baking

soda and baking powder, milk, and butter.

So . . . . . . • While the ingredients may be pure

substances, the batter is not.

• What do we call the batter?

•A mixture!

Can I separate a mixture?

• Turn to page 14-15 K.• Let’s go through those steps and see.

• What about the muffin mix?• Nope! Some of it has begun to interact and begin a

chemical change.

• Afterall, you cannot take all the ingredients and put them back once they are all mixed together and beginning to interact.

Two types of mixtures:

• Heterogeneous Mixtures: you can see the different parts—like a salad.

The other type of mixture:

• Homogeneous mixture: these are so evenly mixed that you cannot see the different parts.

• Sugar or salt water

Remember: all matter has physical and chemical properties.

• Water may freeze, thaw, go to steam, condense back to water and refreeze, however, it is still water; is water; is water!

• But------ it is a change you say?• Yes, but this is a “phase” change.• The water is in a different phase but it is still water.• Let’s show you a physical change with paper and a

two paperclips.

This is fun to show you a change that does not change the substances involved

• Fold your paper like this:

Now hole the two ends of the folded paper and SLOWLY ---------

• Pull in opposite directions until the paper is stretched out.

• Please Do Not pull quickly.• What happened?• The paper clips are hooked together and the

paper is unchanged also. This is a physical change—no one substance is changed. They appear different but they are still paper and paperclips.

What are more words to classify physical properties of matter?

• Dissolvability, luster, can conduct heat and electricity, magnetism, flexibility (can bend w/o breaking).

• Chemical properties-a characteristic of a pure substance that describes its ability to change into different substances.

Want an example of a chemical property?

• With methane (natural gas) it would be that it can catch fire and burn in the air.

• How? As it burns it combines w/ oxygen in the air and forms new substances: water and CO2 (carbon dioxide).

• Burning or flamability is a chemical property of methane, as well as the substances in wood or gasoline which can also burn.

Another example: Iron and oxygen

• What will iron combined with oxygen produce?

• Good old rust!

• What about silver and sulfur in the air?• Tarnish which makes ugly silver.

What do bakers use to produce a chemical change in their breads?

• Yeast.

• The yeast produces a gas and the bread rises.

Let’s try one now:

• In the bag I add a chemical and then water.

• Changes are occurring. Pass the bag around and tell me what you feel.

• A change in temperature to “cold”

How do physical properties differ from chemical properties?

• Chemical properties must combine with something else to form a new substance=a chemical change (The chemical property cannot always be seen).

• Physical properties do not change the substance into something else. (remember the water phase changes). Generally physical properties are descriptions of the substance.

What is an element?

• An element is a pure substance that cannot be broken down into any other substances by chemical or physical means.

• Elements are the simplest substances.

• Here is a periodic table for your journal. Let’s look at it and tell you how to read it.

What is the smallest piece of the element?

• The atom!!• When atoms combine the form a chemical

bond. This bond makes a larger particle called a molecule.

• Like H2O or CO2 or NACL

Compounds

• A compound is a pure substance made of two or more elements chemically combined in a set ratio.

Looking at CO2 = one carbon atom and 2 oxygen atoms. This is a 1 to 2 ratio.

• When elements are chemically combined, they form compounds having properties that are different from those of the uncombined elements.

Quick atom review:

• What is the positive particle of the atom called and where is it located?

• A proton and in the nucleus.• What is spinning quickly out on the far edges of

the atoms and what charge are these?• The electrons and the charge is negative.• What particle has no charge at all and where are

these found?• A neutron and in the nucleus with the protons.