SCIENCE REVISION

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  • Created by: Ellie
  • Created on: 28-04-15 20:13
define thermal decomposition
one molecule breaking down to from new products when heated
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Why does a piece of limestone loose mass when heated?
Because carbon dioxide is given off into the atmosphere and thats the mass that is lost.
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Describe the reaction by which lime (calcium oxide) is made
calcium carbonate (limestone) is thermally decomposed to create calcium oxide (lime)
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The company operating a cement works stated that the smoke particles had not changed from the new fuel. what evidence wold you want to decide if this is true or not?
do a test to compare the smoke particles
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Where is cholesterol produced?
in the liver
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how do statins control the amount of cholesterol in the body?
they block a certain enzyme in the liver that produces cholesterol
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What is a double blind trial?
When neither the doctor nor the patient knows whether the patient has received the the actual drug that is being tested or a placebo.
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Why do people use drugs?
for medical reasons, for recreation/fun, for performance enhancing in sports, just because they're legal.
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How dos the action of a drug make a person addicted?
It changes the chemical processes in your body causing your body to be unable to function without it.
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what is meant by the word 'recreation'?
used for for fun/pleasure
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Why do medicines get tested?
to ensure that it is: safe, effective, stable and can be excreted from the body
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What is Thalidomide?
Was originally developed as a sleeping pill but was then found to prevent morning sickness in early pregnancy. However it had not been fully tested and it was later discovered that it caused birth defects
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What are statins?
Statins are medical drugs which are used to reduce the cholesterol levels in the blood, this reduces the chance of heart disease.
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What is a drug?
A drug is a substance that alters the way in which your body works. it could affect your mind, body or both. some drugs are used for pleasure or recreation, others are used as medicines.
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What system in our bodies do drugs effect?
The nervous system
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Where does convection occur?
in liquids and gases
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How does convection work?
when the fluid is heated the particles gain energy and move more vigorously causing them to move further away and therefore the fluid expands. the volume of the fluid in this region decreases, the density decreases and so the warmer fluid rises above
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Where does conduction occur?
in solids, liquids and gases
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How does conduction work?
vibrating atoms collide, passing energy on. the closer the atoms are the faster the heat energy is passed on & the better the conductor. in metals their ions pass on vibrations & energy. they also contain free electrons which move freely. these elect
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Where does evaporation occur?
in liquids
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how does evaporation have a cooling effect?
The particles with a higher temperature and more kinetic energy leave the liquid first, leaving the cooler particles, with less kinetic energy, lowering the average kinetic energy. the overall then lowers as there's less kinetic energy.
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a tray of marbles is shaken from side to side. as this happens marbles fall out of the tray. explain how this is acting as a model for the evaporation of a liquid.
the marbles act as molecules & as they gain more kinetic energy by being heated, as represented by the shaking of the tray. they leave the liquid or in this case, jump out of the tray- this is is the hotter particles with more kinetic energy evaporating-
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what is the energy transfer equation?
E=MxCxO - energy transferred = mass x specific heat capacity x temperature change
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fill in the gaps- Energy is transferred through metal cad=sing by __________. the warm air rising from the heater transfers energy to the room by __________.
1. conduction 2. convection
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fill in gaps- When a fluid is heated it _______, becomes less _____ and _____. the warm fluid is replaced by cooler, denser fluid. the resulting __________ current _________ energy throughout the liquid.
1. expands 2. dense 3. rises 4. convection 5. transfers
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what happens to the the rate of evaporation if you increase the wind speed?
it causes a greater rate of evaporation
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what happens to the rate of evaporation if you raise the temperature?
it causes a greater rate of evaporation
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what happens the rate of evaporate if there is a higher humidity?
it slows down the rate of evaporation
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what colours are good absorbers of infra-red radiation?
matt, dark colours
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what colours are good emitters of infra-red radiation?
matt, dark colours
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what are ways to insulate homes?
insulate roof or walls, fitting carpets, fitting double glazed window, insulate behind radiators
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what does it mean for a material if it has a lower U-value?
it means it is a better insulating material
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Other cards in this set

Card 2

Front

Because carbon dioxide is given off into the atmosphere and thats the mass that is lost.

Back

Why does a piece of limestone loose mass when heated?

Card 3

Front

calcium carbonate (limestone) is thermally decomposed to create calcium oxide (lime)

Back

Preview of the back of card 3

Card 4

Front

do a test to compare the smoke particles

Back

Preview of the back of card 4

Card 5

Front

in the liver

Back

Preview of the back of card 5
View more cards

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