CHEM 5.1 Properties and Changes

Question 1

What is Chemistry ?

Answer 1

The study of substances: how to change substances into new and usable products in socially and environmentally responsible ways.

Question 2

Physical Properties

Answer 2

A characteristic or description of a substance. Colour, texture, density, smell, solubility, taste, melting point, and physical state.

Question 3

Chemical Properties

Answer 3

A characteristic behaviour that occurs when the substance changes into something new. Corrosivity, flamability, bleaching ability, reaction of an acid with a base.

Question 4

Physical Changes

Answer 4

A change that does not produce a new substance. Changes of state (including melting, evaporation, condensation, sublimation, and dissolving). Many physical changes can be reversed.

Question 5

Chemical Changes

Answer 5

The change that a substance goes through to produce a new substance (or more than one new substance). Many chemical changes cannot be reversed.

Question 6

Evidence of a Chemical Change

Answer 6

1. A new colour appears
2. Heat or light is produced
3. Bubbles of gas are formed (without heat)
4. A solid material (a precipitate) forms in a liquid
5. The charge is (generally) difficult to reverse