A breathable, lightweight material they keeps out water but lets out sweat. This is because the holes are too small for rain to enter but big enough for sweat to leave.
1 of 18
Name two properties scientists are trying to create in a polymer.
Soluble and biodegradable
2 of 18
What are the environmental issues about disposing of polymers?
Land-fill site get filled up; land is wasted; buring produces harmful gases; crude oil is wasted; and it is difficult to recycle polyermers.
3 of 18
Why can some plastics be stretched and melted easily?
Weak intermolecular forces.
4 of 18
Name one property of plastics with strong forces.
Rigid.
5 of 18
Describe the process of 'denaturing'.
Protein molecules change shape and appearance once heat has been added.
6 of 18
What happens to carbohydrates when they are cooked?
The cell walls burst because of swelled up starch; giving them a softer texture and better flavour
7 of 18
What is the word equation for the decomposition of sodium hydrocarbonate?
sodium hydrocarbonate ---> sodium carbonate + carbon dioxide + water
8 of 18
Describe the job of an emulsifier molecule.
The emulsifier molecule has two end - a hydrophilic head and hydrophobic tail. The head bonds with the water molecule and the tail bonds with the oil molecule. The oil molecules then surround the water molecule - keeping the together.
9 of 18
Explain the experiment to make an ester.
An acid is added to an alcohol then heated; a condenser stops gas escaping and cools it down allowing the reaction to go on for longer.
10 of 18
Name five properties of a perfume.
Evaporate easily; non-toxic; not react with water; not irritate skin; insoluble in water
11 of 18
What is a solution a mixture of?
A solvent and a solute
12 of 18
Explain, in terms of kinetic theory, the volatility (evaporation) of a perfume.
Particles need kinetic energy to overcome the forces of attraction. Weak attraction between perfume molecules means less kinetic energy is needed to overcome the attractions.
13 of 18
What is a colloid?
A liquid with dispersed particles but they are not dissolved, eg. paint.
14 of 18
How do emulsion paints dry?
The water from the wet paint evaporates and the oil forms a protective layer over the pigment particles.
15 of 18
How do oil paints dry?
The solvent evaporates and the oil is oxidised by the oxygen in the atmosphere
16 of 18
What can a thermochromic paint be used for?
Show a temperature change on the body; show the temperature of a kettle; show the temperature change for babies objects eg. spoon, bath toy.
17 of 18
Why do phosphorescent paints glow?
The electrons absorb and store energy when the lights are on; when the lights are turned off thy give out energy in the form of light.
18 of 18
Other cards in this set
Card 2
Front
Name two properties scientists are trying to create in a polymer.
Back
Soluble and biodegradable
Card 3
Front
What are the environmental issues about disposing of polymers?
Back
Card 4
Front
Why can some plastics be stretched and melted easily?
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