Using resources Flashcards
What are ceramics?
Non-metal solids with high melting points that aren’t made from carbon-based compounds
Give 2 examples of ceramics
Glass and clay
What is clay and why is it useful?
.Soft when dug up so can be molded into different shapes
.When it’s fired at high temperatures it hardens to form a clay ceramic
.The ability to be molded then harden makes it ideal for bricks and pottery
Describe glass
.Transparent
.Can be molded when hot
.Brittle when thin
How is soda-lime glass made?
Heating a mixture of limestone, sand and sodium carbonate until it melts, when it cools it comes out as glass
How is borosilicate glass made and how is it different from soda-lime glass?
.Higher melting point
.Made in the same way as soda-lime glass, using a mixture of sand and boron trioxide
What is a composite?
.Made of one material embedded in another, fibers or fragments of a material (known as the reinforcement) are surrounded by a matrix acting as a binder
What do the properties of a composite depend on?
The properties of the material its made from
Give 4 examples of composites
Fiberglass, carbon fiber, concrete, and wood
Describe fiberglass, it’s properties and uses
.Fibers of glass embedded in a matrix made of polymer (plastic)
.Low density (like plastic)
.Very strong (like glass)
.Used for things like skis, surfboards, and boats
What things influence the properties of a polymer?
How it’s made and what it’s made from
What do the properties of poly(ethene) depend on?
.The catalyst that was used
.The reaction conditions (temperature and pressure) that it was made under
How low-density poly(ethene) is made and uses
.Moderate temperature
.High pressure
.Catalyst
.Flexible so used for bags and bottles
How high-density poly(ethene) is made and uses
.Lower temperature
.Lower pressure
.Different catalyst
.More rigid so water tanks and drain pipes
Describe thermosetting polymers
.Monomers that form crosslinks between the polymer chains, holds the chain together in a solid structure
.Don’t soften when heated
.Strong hard and rigid
Describe thermosoftening polymers
.Individual polymer chains entwined together with weak forces between the chains
.You can melt and remold these
Properties of ceramics
Insulators of heat and electricity
Brittle
Stiff
Properties of polymers
Insulators of heat and electricity
Flexible
Easily molded
Properties of metals
Malleable Good conductors of heat and electricity Ductile Shiny Stiff
How much carbon is in low carbon steel? Properties and uses
0.1% - 0.3%, easily shaped, car bodies
How much carbon is in high carbon steel? Properties and uses
0.22% - 2.5%, very hard, inflexible, blades for cutting tools, bridges
How is stainless steel made? properties and uses
Chromium added, and sometimes nickel, corrosion resistant, cutlery and containers for corrosive substancs
Bronze =
copper + tin
harder
Brass =
Copper + zinc
Malleable
Low friction
What metals are used to harden pure gold?
Zinc, copper, and silver
How many carats of gold in pure gold?
24
Properties of aluminum
Low density, soft, alloyed to make it harder for use in airplanes
What is corrosion?
Where metals react with substances in their environment and are gradually destroyed
What is the word rust used for?
The corrosion of iron and its alloys (steel)
What is rusted iron actually?
Hydrated iron(III) oxide
What is the word equation for the rusting of iron?
Iron + oxygen + water –> hydrated iron (III) oxide
What happens to the iron in rusting?
It is oxidized
Properties of rust?
Soft and crumbly so flakes off to reveal more iron to rust
Why is the corroding of aluminum not as bad as the rusting of iron?
The aluminum oxide that is formed doesn’t flake away like Hydrated iron(III) oxide and instead forms a protective layer so only the very outer bit gets corroded
How to show iron needs both water and oxygen to rust
.Boil water to remove oxygen, put in a test tube, put a nail in the tube, put oil on top to stop oxygen entering, nail won’t rust
.Put calcium chloride in a tube to remove water, put a nail in the tube, t won’t rust
.Put a little bit of water in a tube, put a nail in the tube so its half covered in water and half in the air, it will rust
3 types of barrier methods to prevent rusting
.Painting/coating with plastic - ideal for big and small and can be decorative
.Electroplating - uses electrolysis to reduce metal ions onto an iron electrode, can be used to coat the iron with a layer of a different metal that won’t be corroded away
Oiling/greasing - used when moving parts are involved, like a bike chain