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62 Cards in this Set
- Front
- Back
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What are all materials made up of |
Chemicals |
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What are chemicals made up of |
Atoms or groups of atoms bonded together |
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What materials occur naturally |
From plants:
Wood & paper from trees Cotton from plants
From animals:
Wool from sheep Silk from silk worms Leather from cows |
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What does synthetic mean |
Made by humans - rubber, clothes (made from man made materials eg polyester or nylon), paint
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Where do the raw materials used to make synthetic materials come from |
they come from the earths crust eg aluminium and chlorine |
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The 5 different properties different materials have |
Melting point Strength Stiffness Hardness Density |
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Strength |
How good a material is at resisting another force - judged by force needed to break it or permanently change its shape |
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Stiffness |
How good a material is at not bending - can be strong if a big force doesn't permanently deform it |
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Hardness |
How difficult it is to cut it |
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Density |
Mass per unit volume (g/cm2) |
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Plastics properties |
-Can be hard, strong and stiff -Low density -Some are mouldable (easily made into things) |
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Rubber properties |
-Strong but soft and flexible -Mouldable |
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Nylon fibres |
Eg rope & clothing fabric Soft and flexible Good tensile strength |
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Effectiveness of product |
How good it is at the job it's supposed to do |
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Gramophone records |
100 yrs ago We made a mixture of matierials - paper, slate & wax - there weren't many because they broke easily |
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How is crude oil formed |
Formed from the buried remains of plants and animals - it's a fossil fuel |
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What is crude oil |
It's a mixture of hydrocarbons - molecules that are made of chains of hydrogen atoms only |
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What changes in hydrocarbon as chain gets longer |
Properties - short chain molecules have low boiling points - often gases |
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2 important types of bond in crude oil |
Covalent bonding Intermolecular bonding |
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Strong covenant bonding |
Bonds between carbon & hydrogen within each hydrocarbon molecule |
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Intermolecular bonding |
Forces of attraction between different Hydrocarbon molecules in the mixtures |
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What happens when crude oil mixture is heated |
Molecules are supplied with extra energy which makes the molecules move about more - could eventually overcome the intermolecular forces keeping it with other gasses - whiz off as a gass |
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Which one is stronger covenant bond holding molecules together or intermolecular forces |
Covalent bonds are much stronger |
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Gramophone records |
100 yrs ago We made a mixture of matierials - paper, slate & wax - there weren't many because they broke easily |
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How is crude oil formed |
Formed from the buried remains of plants and animals - it's a fossil fuel |
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What is crude oil |
It's a mixture of hydrocarbons - molecules that are made of chains of hydrogen atoms only |
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What changes in hydrocarbon as chain gets longer |
Properties - short chain molecules have low boiling points - often gases |
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2 important types of bond in crude oil |
Covalent bonding Intermolecular forces |
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Strong covenant bonding |
Bonds between carbon & hydrogen within each hydrocarbon molecule |
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Intermolecular bonding |
Forces of attraction between different Hydrocarbon molecules in the mixtures |
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What happens when crude oil mixture is heated |
Molecules are supplied with extra energy which makes the molecules move about more - could eventually overcome the intermolecular forces keeping it with other gasses - whiz off as a gass |
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Which one is stronger covenant bond holding molecules together or intermolecular forces |
Covalent bonds are much stronger |
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Gramophone records |
100 yrs ago We made a mixture of matierials - paper, slate & wax - there weren't many because they broke easily |
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How is crude oil formed |
Formed from the buried remains of plants and animals - it's a fossil fuel |
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What is crude oil |
It's a mixture of hydrocarbons - molecules that are made of chains of hydrogen atoms only |
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What changes in hydrocarbon as chain gets longer |
Properties - short chain molecules have low boiling points - often gases |
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2 important types of bond in crude oil |
Covalent bonding Intermolecular forces |
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Strong covenant bonding |
Bonds between carbon & hydrogen within each hydrocarbon molecule |
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Intermolecular bonding |
Forces of attraction between different Hydrocarbon molecules in the mixtures |
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What happens when crude oil mixture is heated |
Molecules are supplied with extra energy which makes the molecules move about more - could eventually overcome the intermolecular forces keeping it with other gasses - whiz off as a gass |
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Which one is stronger covenant bond holding molecules together or intermolecular forces |
Covalent bonds are much stronger |
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How is crude oil separated |
By fractional distillation - hydrocarbons are separated into groups with different boiling points (fraction) - hydrocarbons within a fraction have similar boiling points |
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Uses of crude oil |
Petrochemical industry's refine crude oil to produce fuel & lubricants - also produces raw material to make synthetic chemicals
Most hydrocarbon are used to make fuel
A small amount is used to make new compounds such as plastic, medicine, fertilisers
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What's chemical synthesis |
Process of making new compounds |
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What's chemical synthesis |
Process of making new compounds |
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What's polymerisation |
Loads of small molecules linking together |
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How is polymer formed |
Under pressure many small molecules (monomers) polymerise to form long chains called polymer |
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Different types & uses of polymer |
Strong & rigid used to make plastic milk bottles - high density
Light & stretchable used in plastic bags & squeeze bottles - low density
PVC is strong & duable - either rigid (piping) or stretchy (synthetic leather)
Polystyrene foam used in packaging to protect breakable things
Heat resistant polymers, used in plastic kettles |
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Examples of polymers replacing natural materials |
Synthetic fibres nylon & polyester offer replace cotton wool or silk fabrics
Adv: lighter, more durable (with stand pressure) & cheaper
Disadv: synthetic fibres aren't breathable - uncomfortable next to skin |
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Another example |
Rigid PVC replaced wood for window framing
Adv: water resistant & durable - Windows more secure Disadv: doesn't look as nice |
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Factors of polymer with weak forces between the different chains |
Free to slide over each other - means plastic is stretched easily & has low melting point - easier to break |
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Strong forces |
Have high melting points & can't easily be stretched as cross links hold chains firmly together |
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What are cross links |
Chemical bonds between the polymer chains |
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How can polymers be made stronger |
By adding cross-linking agents, they chemically bond chains together making them stronger, stiffer & more heat resistant |
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How can polymers be made stronger |
By adding cross-linking agents, they chemically bond chains together making them stronger, stiffer & more heat resistant |
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What can make polymers softer & easier to shape |
Plasticisers, they get between polymer chains reducing the forces between them |
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Crystalline polymer |
They have straight polymer chains
Can fit close together
Higher density, stronger & higher melting point than branches polymer |
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Natural nanoscale materials |
Seaspray - salt particles which are present in the atmosphere
Combustion - soot particles produces when fuels are burnt |
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Why are nanoparticles added to materials |
Make them stronger & more durable & they don't add weight eg tennis racket, golf ball |
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Why are nanoparticles added to materials |
Make them stronger & more durable & they don't add weight eg tennis racket, golf ball |
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Silver nanoparticles |
Kill bacteria |
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What is Nanotechnology |
Branch of technology dealing with making use of nanoparticles |
