8th grade Science: Chapter 1 Introduction to Matter

Matter

anything that has mass and takes up space.

Chemistry

the study of matter and how matter changes.

Substance

a single kind of matter that is pure, meaning it always has a specific makeup, or composition.

What properties describe matter?

Physical properties and chemical properties.

Physical Property

a characteristic of a substance that can be observed without changing it into another substance.

Chemical property

a characteristic of a substance that describes its ability to change into different substances.

Physical property example

Chemical property example

What is matter made of?

more than 100 different substances called elements.

Element

a substance that cannot be broken down into any other substances by chemical or physical means.

Atom

the basic particle from which all elements are made.

Atom consists of

Positively charged center, or nucleus, containing smaller particles.

Chemical bond

When atoms combine; which is a force of attraction between two atoms.

Molecule

a group of two or more atoms held together by chemical bonds.

Keys

C= Carbon
H=Hydrogen
O= Oxygen
N= Nitrogen

Compound

a substance made of two or more elements that are chemically combined in a set ratio.

Solution

a homogeneous mixture with tiny particles. The particles are too small to see and also too small to settle or be filtered out of the mixture.

Chemical formula

represents a compound, which shows the elements in the compound and the ratio of atoms.

Mixture

made of two or more substances that are together in the same place, but their atoms are chemically bonded.

Two types of mixtures

heterogeneous or homogeneous.

Heterogeneous mixture

You can usually see the different parts and they can easily be separated out. Ex: salad

Homogenous mixture

The substances involved are so evenly mixed that you can't see the different parts. Ex: honey

Mass

The amount of matter in an object; which does not change with location even if the force of gravity changes.

International System of Units

To measure the properties of matter, scientists use a system SI units.

kg

The SI unit of mass.

Volume

The amount of space that matter occupied.

cubic feet (m3)

SI unit of volume

Volume formula

Length x width x height

Density

Is a measure of the mass of a material in a given volume.

Density formula:

Density= mass/volume

Density

can be expressed as the number of grams in one cubic centimeter (g/cm3)