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Science Module Form 1- Chapter 4
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CHAPTER 4 : THE VARIOUS RESOURCES ON EARTH
Importance of water to humans and animal :
Carries nutrients to all cells in our body.
Removes waste (urea) in the urine and sweat.
Dissolves chemicals for metabolic activities in cells.
Comprises 90% of the cell’s protoplasm.
Importance of water to plants: Makes food during photosynthesis.
Transports organic material (glucose).
Supports aquatic plants to stand in water.
Importance of living things to human :
Provides food as source of energy to carry out living process.
Provides building material. Provides clothes to protect body from cold and heat.
Importance of soil :
Habitat for living things. Humus fertilizes the soil and suitable for farming.
Contains mineral salts needed for the growth and development of plants.
Found in the soil. Importance of mineral :
Steel is used for constructions Copper is used to make electric cables.
Importance of oxygen : For respiration of living cell. Needed in burning.
Importance of carbon dioxide : Produces food during photosynthesis.
Composition in fire extinguishers.
Importance of nitrogen : Produces fertilizers. Fills light bulbs to prevent the filament from oxidation.
Example : Coal, petroleum and natural gas.
Used to generate electricity in power station.
Burning of fossil fuels provide energy to vehicles.
Science Module Form 1- Chapter 4
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CHARACTERISTICS
A substance which made up of only one type of atom , cannot be broken down into any simpler substances by chemical or physical method.
Atom – elements consist of individual particles. - examples : Copper, Aluminium, Zink, Iron, Gold.
Molecule – elements consist of combined atoms of the same type. - examples : Oxygen gas, hydrogen gas.
METALS NON- METALS
PROPERTIES Good electrical conductors Good heat conductors High melting points Shiny appearance High densities Malleable Ductile Sonorous Examples : Aluminium, Gold, Copper, Zink, Iron.
PROPERTIES Poor electrical conductors Poor heat conductors Low melting points Dull appearance Low densities Brittle Non-ductile Non- sonorous Examples : Bromine, Sulphur, Carbon, Phosphorus, Iodine.
USES Copper – makes water pipes and electrical cables. Gold - as jewellery. Aluminium – makes air craft body. Iron – makes cooking utensils. Tin – as coating of food cans.
USES Carbon – as pencil leads Diamond - cut glass and make jewelleries. Sulphur – firecrackers and tyres. Nitrogen – fertilizers.
Science Module Form 1- Chapter 4
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Compound Elements present
Sodium chloride (salt)
Sodium, chlorine
Copper sulphate Copper, sulfur, oxygen
Calcium carbonate (chalk)
Calcium, carbon, oxygen
Petrol Hydrogen, carbon
Sand Silicone, oxygen
Sugar Carbon, hydrogen, oxygen
Carbon dioxide carbon, oxygen
Water Hydrogen , oxygen
DEFINATION Compound are substances made up of two or more elements which are chemically combined.
Molecule is the smallest particle in a compound.
Examples : A water molecule is made up of two hydrogen atoms and one oxygen atom.
PROPERTIES Formed by chemical reaction which involve exchange of energy.
Properties of compound differs from the properties of its constituents elements.
The compound can only be broken down into its elements by chemical methods such as electrolysis.
The elements in a compound are joined together in a definite ratio.
EXAMPLES Sugar Sand Carbon dioxide Salt Chalk
EXAMPLES OF COMPOUNDS
Science Module Form 1- Chapter 4
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Mixture Components
Air Nitrogen, oxygen, carbon dioxide, dust, rare gases, microorganisms.
Orange juice Orange juice, water, sugar
Sea water Water, mineral salts
Brass (alloy) Copper, zinc
Blood Plasma, blood cells, nutrients, waste products.
Steel Iron, carbon
Coins Copper, nickel, tin
Coffee drink Coffee powder, water, milk, sugar
DEFINATION
� A mixture consist of two or more substances that have been combined physically. � Mixtures can be formed by mixing
Different elements Different compounds Elements and compounds
� Examples : air, soil, orange juice, sea water, milk and etc.
PROPERTIES
� Formed by physical methods which does not involved chemical reactions � Properties of constituents in a mixture is preserved. � Can be separated easily through physical methods. � The substances in a mixture can be mixed in indefinite ratio.
EXAMPLES OF MIXTURES AND THEIR COMPONENTS
Science Module Form 1- Chapter 4
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MIXTURE SEPARATING TECHNIQUES
Science Module Form 1- Chapter 4
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DIFFERENCES BETWEEN COMPOUND AND
MIXTURES
COMPOUNDS MIXTURES
Aspect
Formed through chemical methods Formation method
Formed through physical methods
Formed new substances New substances
formation Does not form new
substances
Absorbed or release heat energy Energy changes
Does not absorb or release heat energy
Differ from the compounds
Combines in fixed ratio
Cannot be identified
Can use chemical method
Combination ratio of substances
Identification of constituents
Properties of constituents
Separation technique of constituents
Combines in any ratio
Easily identified
Preserved
Can use physical method
