Download - Ch.9.properties of matter and matterials
Properties of matter and materialsChemistryChapter 9
Elements
A substance that has only one kind of atom.
93 elements are natural, while 24 are man made.
Molecules
A substance made of groups of one or more element.
Metals and non-metals
- Scientists divided all the elements into 2 groups: Metals and non-metals
Look at the following pictures and describe some of their properties
Metal Non-metal
Property Metal Non-metalSurface Shiny Dull
Physical state at room temp.
Usually solid Solid, liquid or gas
Strength Shaped by pressing and stretching
without breaking easily
Soft or brittle
Melting point Usually high Usually lowBoiling point Usually high Usually low
Density Usually high Usually low Conduction of heat Good Very poor
Conduction of electricity
Good Very poor
Non-metal UseChlorine - Purify water (kills
microorganisms)- In swimming pools (keeps the
water clean)Phosphorus - Used on tip of matchesIodine - Used in some portable water
purifying kits (used by people who take adventure holidays)
- Some metals and non-metals are exception to the rules.
Example:- Magnesium (metal), but it has a dull surface.
- Graphite (non-metal), conducts electricity.
- Iodine (non-metal), shiny surface
The properties of materials
- There are a number of properties that materials may have.
1) Surface appearance
- Shiny, dull, rough or smooth
2) Rigid- Cannot be bent or squashed.- Example: Rock
3) Flexible
- Can be bent or squashed.- Example: Flexible piece of
wood (Used as bows)
4) Hard or soft
- Usually hard materials are rigid and soft materials are flexible.
5) Malleable
- Materials that can be shaped by hammering or pressing.
- Example: Gold, silver and copper are malleable
6) Brittle
- Materials that break suddenly when they are bent or hit.
- Example: Biscuit or chocolate bar
7) Absorbent
- Materials have holes in their surface to let the water pass through and have spaces inside where the water can collect.
- Some rocks (sandstone and limestone) have gaps(pores) they are porous.
8) Waterproof
- Materials that do not pass water through.
Water resistant
Water repellent- Made of fibres.
- There are holes between the fibres (water passes through)
- Fibres are coated with silicones (does not allow water to be absorbed)
- Used to make: Umbrellas, outdoor jackets and trousers
- Do not have any holes in it through which water can pass
- Used to make: Wellington boots
9) Transparent
10) Translucent
11) Opaque
- Lets light pass through it (can see objects clearly through it).
- Lets some of the light pass through
- Do not let the light pass through
12) Heat conductor
13) Heat insulator
- Allows heat to pass through
- Does not allow heat to pass through
14) Electrical conductor
15) Electrical insulator
- Allows electricity to pass through
- Does not allow electricity to pass through
Property profile
- A description of a material in term of its properties is called a property profile.