Science 5.3 notes

What is a chemical change?

A chemical change happens when a substance changes into one or more different substances.

What is a physical change?

A physical change in matter only effects the form/state, not the substance.

Describe change.

Change happens all the time, whether it's quick or slow, or big or small.

What are changes classified?

Changes are classified either physical or chemical.

What are characteristics of chemical changes?

Chemical changes are usually irreversible. When the change occurs, a new substance forms with a new set of properties. Also, energy change may occur.

What is an example of a physical change?

Chopping a piece of wood is an example of a physical change. Only the form of the wood changes, not the substance itself.

What is condensation?

Condensation is when heat is removed from gas, turning it into liquid. An example is when a bathroom mirror fogs after a hot shower.

What is deposition?

Deposition is the term describing when heat is removed from gas, turning it into a solid. Frozen patterns on a car windshield on a winter day is a form of deposition.

What is dissolving?

Dissolving is a physical change when a substance (solute) becomes incorporated into a liquid, creating a solution. Mixing sugar in water is an example.

What is evaporation?

Evaporation is the term describing when heat is added to liquid, turning it into gas. A hot drink that's cooling down is a form of evaporation.

What are some examples of change?

Examples of change include when your skin cells are being replaced with new ones and when a piece of paper burns into ash.

Are chemical changes reversible?

Most chemical changes are permanent and not reversible. For example, a burnt marshmallow cannot change into a fresh one.

What are characteristics of physical changes?

Physical changes are usually reversible. When the change occurs, properties and substances remain the same. Also, energy change may occur, but may not be noticed.

What is an example of a reversible chemical change?

Rechargeable batteries are examples of reversible chemical changes. In one chemical reaction, substances in the battery change into new substances. In a different chemical reaction, the new substances can change back to the original substances.

What is solidification?

Solidification is when heat is removed from a liquid, turning it into a solid. Water freezing into ice is a form of solidification.

What is sublimation?

Sublimation is when heat is added to a solid, turning it into gas. Dry ice is a form of sublimation.

What are the six terms that are used to describe the different changes of state?

The six terms are evaporation, condensation, deposition, sublimation, melting and solidification.

What is the term melting?

The term melting is used to describe a substance when heat is added to a solid, turning it into liquid. Ice melting into water is an example.

Is it possible for a change to be both physical and chemical? If so, give examples.

Yes, a change can be both physical and chemical. Wood rotting and a candle burning are examples.