4.2 Properties of Matter

1. 4.2 Properties of Matter (Sec 5.2 pg 157)

2. Every substance is unique, and have distinguishing characteristics that allow us to tell them apart. • The characteristics that describe a substance are called its properties. In the same way that you have properties that describe you (short, tall, fast, funny, etc) substances have properties that describe them.

3. There are two categories of properties. • Physical properties describe the characteristics you can detect with your senses. Melting point, density, etc. • Chemical properties describe how the substance reacts with other chemicals.

4. Let’s look at physical properties first. • State of Matter: • Is it a solid, liquid, or gas at room temperature?

5. Let’s look at physical properties first. • Melting point/Boiling point: • What temperature does it melt and boil at?

6. Let’s look at physical properties first. • Malleability: • This is another way of saying that something can bend without breaking. Metals are malleable.

7. Let’s look at physical properties first. • Ductile: • This means that something can be stretched without breaking. Many metals can be pulled or stretched into thin wires.

8. Let’s look at physical properties first. • Solubility: • How much of something will dissolve in a quantity of liquid.

9. Let’s look at physical properties first. • Conductivity: • Will the object conduct electricity or not? Metals are very conductive.

10. Let’s look at physical properties first. • Density: • This is mass ÷ volume. Usually measured in g/ml.

11. Now let's take a look at the chemical properties. • Chemical properties describe how a substance reacts with other chemicals. • Flammability – This is the measure of how easily something burns (a fast reaction with oxygen). It can be used to heat our homes, run our cars, but it can also be destructive and must be treated with respect.

12. Chemicalproperties describe how a substance reacts with other chemicals. • Corrosion – This is a measure of how easily something corrodes (a slow reaction with oxygen). Rusting is an example.

13. Chemicalproperties describe how a substance reacts with other chemicals. • Reactions with Acid – Some metals react with acid to produce hydrogen and other gases. Minerals can also react to produce gases.