Classification of Matter & Physical/Chemical Changes

Matter

Anything that has mass and takes up space (volume)

Homogenous

Composition that appears uniform throughout

Heterogenous

components that do not have a uniform composition

Element

The simplest type of matter that consists of a single atom.

Homogenous

Pure substance

Compound

Two elements combined together chemically in the same proportion

Homogenous

Pure substance

Solution

Made of two parts: the solute and the solvent.

The solute is the small particles that pass through filters or semi permeable membranes.

Homogenous

Mixture

Colloid

A mixture that has particles that are moderately large: they can pass through filters but not semi permeable membranes

Heterogenous

Mixture

Suspension

Mixtures with solute particles that are large and heavy enough to settle and be retained by filters and semi permeable membranes

Heterogenous

Pure substance

Matter that consists of just one type of atom, molecule or compound

Mixtures

Two or more different substances that are physically mixed

Physical change

When the physical properties like stage, size, or appearance of a substance change but its chemical identity stays the same.

Ex: water boiling to form a vapor, paper cut into tiny pieces of confetti, sugar dissolving to form sugar solution

Chemical change

A change which the original substance is converted into a new substance that has a different composition and new physical and chemical properties.

Ex: iron rusting to form iron oxide, water and cesium combining explosively, heating sugar to form a smooth, caramel colored substance, and paper burning.

Types of physical changes

1. Phase changes

2. Mechanical changes

3. Dissolving is always a physical change

4. Crystallization

What are the signs of a chemical change?

1. Bubbles forming is evidence of gas being formed

2. Color change

3. Temperature change

4. Fire/explosion

5. Formation of a precipitate

6. Odor change

Intensive properties

Independent of the amount of the substances

• it doesn’t matter how much you have, they always stay the same

• We use these to identify substances

• Ex: color, boiling point, and density

Extensive properties

Depend on the amount of substance

• ex: mass, length, and shape