CHAPTER 4THE VARIETY OF RESOURCES ON
EARTH
Resources on Earth
Living things
Animals
Plants
Non living things
Air
Water
Fossil fuels
Natural Gas
Petroleum
Coal
Soil
4.1 Natural Resources on Earth
4.2 Understanding Element, Compound and Mixture
Matter
Element
Metal
Nonmetal
Compound Mixture
Video 1: Elements http://www.youtube.com/watch?v=d0zION8xjbM
Element
• Element: a substance that consists one type of atom only.
• It is the simplest matter and cannot be separated by any chemical or physical method.
Atom Molecule
Classification of ElementElement
Metal- In solid form except for mercury (liquid)
-Eg: calcium, copper, gold, lead
Non metal-Exist in all states
(solid, liquid and gas) at room
temperature.-Eg: sulphur, carbon,
bromine, oxygen
Surface
Melting and boiling point
Electric Conductivity
Malleability
Ductility
Heat Conductivity
Shiny
Malleable
Ductile
Good
Good
High
Dull
Not malleable
Brittle
Weak
Do not conduct, except Carbon
Low
Met
als
Non M
etals
Density High Low
Surface
• The surface of metals are usually shiny when polished compared to nonmetals.
Malleability
• Malleability is the ability of a metal to be hammered, rolled, or pressed into various shapes without rupture or fracture.
Malleability
Ductility
• Ductility is the ability of a metal to be bent or stretched permanently without rupture or fracture.
• Metals that lack ductility will crack or break before bending.
Ductility
Nonmetal- silicon Metal- aluminium
Heat Conductivity
• The ability to transfer heat.• Which material is easier to get hot? Metal or
nonmetal material?
Electric conductivity
• The ability of transferring electricity.
Melting and boiling pointDensity
• Most metals are solid (except for mercury), therefore it requires more heat to melt them.
• Since metals are mostly solids, their mass are higher, thus their densities are all high.
Properties of metals
Video 2: http://www.youtube.com/watch?v=anRdgl4D5KI
Compound • A compound is a substance that contains two
or more atoms chemically combined together. • The components in compound can only be
separated through chemical reactions such as electrolysis or heating.
Mixture • A mixture is a combination of two or more
substances that have been mixed physically; for example by stirring.
• A mixture may consists of elements, compounds or both.
Video 3: http://www.youtube.com/watch?v=cL6I1O1YHH0
The differences between compound & mixture
Formation
Separation
Formation of new substance
Properties of components
Conversion of energy
Chemically formed
New substance is formed
New properties
Heat energy is released
Can be separated chemically
Physically mixed
No new substance is formed
Retain its original properties
Heat energy is not released
Can be separated physically
Compound Mixture
Identification of components
Components that make up compound cannot be
identified
Components of mixture can be identified easily
Electrolysis of Copper (II) Sulphate: Separating a compound
Video 4: http://www.youtube.com/watch?v=Q62UfP-ZADY
When sugar is heated, it will be
broken into carbon and water
Examples of mixtures
Separation of mixture: Physical methods
Filtration: to separate insoluble
solids
Evaporation: to separate dissolved solid particles from
its solvent
Distillation: to separate a solvent
from a liquid or solid-liquid mixture.
Using magnet: to separate
substances which are attracted to a
magnet from nonmagnetic substances.
Sieving: to separate mixture
of solid substances with different sizes.
Extraction: to separate liquid substances that do not mix well
and with different densities
Chromatography: to separate coloured components in a mixture
4.3 Appreciating The Importance Of The Variety OfEarth’s Resources To Man.
OxygenBreathing, cell respiratin, combustion, burning
Carbon dioxideTo put out fire, for photosynthesis
SoilHabitat for many types of living things
Minerals Soil contains minerals and water which is vital for growing of plants
Fossil fuelsTo provide energy for household use, factories and power stations to generate electricity.
Water Regulates body temperature, controls the concentration of blood
Living thingsAs food, medicine, fibre, building materials, and so on.
Conservation And Preservation
• Conservation: involves the intelligent use and care of our resources.
• Preservation: the act of keeping the resources in their original state.