Science

Chapter 4

Lesson 16Physical and Chemical Properties

TCAP Coach

Objective:

SPI 0507.9.1

Distinguish between physical and chemical properties.

Physical and Chemical Properties

All objects and materials are made up of matter.

Matter is anything that has mass or weight and takes up space.

A cube of sugar is a kind of matter, as a drop of water and a tank of oxygen gas.

All kinds of matter can be described by their properties, or characteristics.

Physical Properties

A physical property is a characteristic of a substance that you can observe without changing the substance into a different one.

You can observe physical properties with your fives senses- sight, hearing, touch, taste, and smell.

Physical Properties

Example: You can use your sense of sight to observe the shape, size, and color of a cube of sugar.

You can also use your sense of sight to tell you that the lump of sugar is a solid.

You use your sense of taste to tell you that the sugar is sweet.

You use your sense of touch to discover that the cube is rough and gritty.

You can sue your sense of hearing and smell to find out the sugar does not make sound and does not have a strong odor.

Physical Properties

You can also use your sense of sight to make some measurements.

Measurements can help you figure out the density of a material.

Density is an object's mass divided by it's volume.

Mass is the amount of matter, or “stuff” that makes up an object.

Volume is the amount of space an object takes up.

Physical Properties

Different materials have different densities. The more mass an object has in a certain amount of space, the denser it is.

Physical Properties

A cube of sugar has a lower density than a cube of iron that is the same size.

Iron has more mass packed into the same amount of space.

Substances with lower densities float on top of substances with higher densities.

That is why a steel paper clip sinks in a glass of water.

The paper clip has a higher density.

Some Physical Properties

Temperature Volume Density Color Shape Solubility Mass Size Conductivity

Physical Properties

Texture is the way an object's surface feels when you touch it.

Imagine that you are describing a glass marble to your friend.

You might describe the marble as green, odorless, and smooth. Gritty, rough, greasy, or glassy are other words that can describe textures.

Physical Properties

Conductivity is another physical property of matter that can be measured.

Conductivity is the ability of a material to let electrical energy pass through it.

Substances that are good conductors of electrical energy are also good conductors of heat.

As a general rule, metals have greater conductivity compared to nonmetals.

Physical Properties

Another physical property of matter is its state.

A state of matter is the form the matter takes, such as solid, liquid, or gas.

Chemical Properties

A chemical property is a characteristic that determines how a substance will react with other substances.

You cannot observe a chemical property of a substance without changing it into a different substance or substances.

Chemical Properties

Example: If a lump of coal is heated enough, it will react with oxygen in the air.

That reaction is called burning. Coal is mostly made up of solid substances

that contain carbon. When coal burns, the materials in it are

changed to a gas called carbon dioxide and to water.

The ability of coal to burn is one of its chemical properties.

Chemical Properties

Other substances also have this chemical property. Examples: wood, oil, gasoline, paper,and

natural gas. A substance like iron does not burn when oxygen is

present, but iron does react with oxygen very slowly.

If it is left out in the open long enough, part of an iron nail will react with oxygen to make rust.

Rust is not iron or oxygen. Rust is a completely new substance.

The ability of iron to turn to rust is one of its chemical properties.

Chemical Properties

Another chemical property is the ability of some metals to react with an acid.

Example: If you drop a chunk of metal zinc into a strong acid, a change happens. Bubbles of hydrogen gas come out of the acid. A new solid substance forms.

Chemical Properties

Water has interesting chemical properties. If you pass electricity through it, it breaks

into parts that make it up. The parts are oxygen and hydrogen. One of these substances is given off as

bubbles where the electricity enters the water. The other substance is given off as bubbles where the electricity leaves the water.

Chemical Properties

The pictures below show how the chemical properties of substances can produce new materials.

1. Which one is an example of a chemical property?

A. the color of a substance

B. the density of a substance

C. whether a substance burns

D. the mass of a substance

1. Which one is an example of a chemical property?

C. whether a substance burns

2. Which one is an example of a physical property?

A. the ability of a substance to react with an acid

B. a substance's texture

C. the ability of a substance to be broken down by electricity

D. the ability of a substance to rust

2. Which one is an example of a physical property?

B. a substance's texture

3. What is density?

A. the mass of a substance divided by its volume

B. the volume of a substance divided by its mass

C. the mass of a substance

D. the volume of a substance

3. What is density?

A. the mass of a substance divided by its volume

4. Which material is MOST LIKELY to have the greatest conductivity?

A. wood

B. water

C. paper

D. gold

4. Which material is MOST LIKELY to have the greatest conductivity?

D. gold