Module C2 - Material Choices Flashcards
What is water made from?
It is a chemical made up of water molecules. It is made up of hydrogen elements and oxygen elements.
Name materials made from plants.
Wood and paper are made from trees. Cotton comes from the cotton plant.
Name materials made from animals.
Wool comes from sheep. Silk is made from silkworm larva. Leather comes from cows.
What is iron made from?
It is a chemical element made of iron atoms.
What is the advantage of synthetic rubber over natural rubber?
It is easier to control its properties so it makes it suitable for lots of different purposes.
What is stiffness?
A stiff material is good at not bending when a force is applied to it. Steel is very stiff as it is so hard to bend.
What is strength?
Strength is how good a material is at resisting a force. It can be judged by how much force is needed to either permanently change its shape or break it.
What is tensile strength?
How much a material can resist a pulling force. Cables and ropes must have a high tensile strength so they don’t snap.
What is compressive strength?
How much a material can resist a pushing force. Bricks should have a high compressive strength so they are not squashed by bricks above.
What is hardness?
How difficult it is to cut into. Diamond is the hardest material found in nature.
What is density?
A material’s mass per unit volume. Air isn’t dense whereas gold is very dense. Objects that are less dense that water will float (ice). Objects that are more dense than water will sink.
What are the properties of plastics?
Can be hard, strong and stiff. Fairly low density. Mouldable.
What are the properties of rubber?
Strong yet soft and flexible. Mouldable.
What are the properties of nylon fibres?
Soft, flexible and good tensile strength.
What are hydrocarbons?
Molecules made of chains of carbon and hydrogen atoms.
How does the length of the carbon Jains affect the boiling point?
Short chain molecules have lower boiling points and are often gases. Long chain molecules have high boiling points and can be viscous (thick and stick).
Name the two bonds in crude oil.
Strong covenant bonds between the carbon and hydrogen atoms within each hydrocarbon molecule. The intermolecular forces of attraction between different hydrocarbon molecules in the mixture.
Why do big molecules have higher boiling points?
Because they have higher forces of attraction therefore more energy is needed to break them out of a liquid to form a gas.
What is the process of separating crude oil called? Briefly describe it.
It is called refining and it is done by fractional distillation. Hydrocarbons are separated into groups, called fractions, with different boiling points. The use of a hydrocarbon will depend on the length of its molecule chains.
Name the useful products of crude oil, from those with the shortest chains to those with the longest chains.
Refinery gas. Petrol. Naphtha (a base for many chemicals). Kerosene (jet fuel). Diesel. Lubricating oil. Bitumen (used for road surfaces).
What is chemical synthesis?
It is the process of making new compounds. This is done when useless hydrocarbons are split apart to make more useful hydrocarbons and ethene.
How are polymers formed?
When monomers join together, under high pressure.
If a polymer is strong and rigid, what can it be used to make?
Plastic milk bottles.
To make PVC, what kind of properties are desirable?
Strong and durable. It can also either be rigid, to make window frames and piping, or stretchy, to make synthetic leather.
