Physical vs Chemical Change

Concept 7: Physical vs. Chemical Change

Success Criteria & Vocabulary

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  • I can identify physical and chemical changes.

  • I can explain the differences between physical and chemical changes.

Click this drop-down menu to see the list of Vocabulary.

Chemical change: Irreversible change in matter where new products are formed.

Condensation: The process whereby particles in a gas lose energy and become a liquid.

Deposition: The process whereby particles in a gas lose energy and become a solid.

Evaporation: The process whereby particles in a liquid gain energy slowly and become a gas, without producing bubbles.

Freezing: The process whereby particles in a liquid lose energy and become a solid.

Melting: The process whereby the particles in a solid gain energy and become a liquid.

Physical change: Reversible change in matter where no new products are formed.

Sublimation: The process whereby particles in a solid gain energy and become a gas.

Tasks

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Task called 'Physical and Chemical Changes'.

Concept 7: Support Notes

Physical Change

PHYSICAL CHANGES do not produce a new substance.

This means no new products are formed. As a result, there is no change in temperature, colour, and smell. Gases are not produced. so bubbles won't be present.

Examples are:

  • Changes in state (MELTING, FREEZING, EVAPORATION, CONDENSATION, SUBLIMATION etc.)

  • Bending a piece of wire

  • Breaking a bottle.

Usually, physical changes are reversible.

Chemical Change

A CHEMICAL CHANGE occurs when a new substance is formed and is not easily reversible.

Observations to show a chemical change could be a colour change, a new smell, the chemicals getting hotter or colder or a gas is produced.

For example:

  • Burning wood - temperature change

  • Mixing acid with universal indicator - colour change

  • Seeing bubbles when vinegar and baking soda are mixed - a gas is formed

  • Burning sulfur - creates a new smell.

Observing Reactions

To observe reactions means to record or make note of something we have experienced. We also think of observations as watching something, but in Science, observations may be made with any of our senses (by seeing, feeling, hearing, tasting, or smelling) or even using tools to make observations that are then changed into something our senses detect.

Observation tools include thermometers, miceoscopes telescopes, radars, computer sensors, and probes. Sometimes these tools can observe and collect data that humans cannot directly sense. By using these tools, scientists can often make many more observations and much more precisely than our senses are able to.