Chemistry OCR C1

what is an atom?
they make up everything that exists
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what are molecules?
atoms joined with other atoms
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what are compounds?
molecules containing different types of atoms.
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what do atoms form to make molecules or compounds?
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what is involved when a bond is made?
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how are electrons charged?
electrons have a positive charge if they have gained atoms and have a negative charge if they lose atoms
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what are food colourings used for?
to make food look more appealing
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what are flavour enhancers used for?
to bring out flavours in food
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what are antioxidants used for?
preserving food
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what are emulsifiers used for?
to help oil and water blend
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give examples of what food emulsifiers are used in.
ice cream, low fat spread, mayonnaise
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what is it called when oil and water are mixed?
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what are emulsions made up of?
droplets of one liquid suspended in another liquid.
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what are emulsifiers?
molecules with one part attracted to water (hydrophilic) and the other part is attracted to oil (hydrophobic)
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what happens when you use an emulsifier with oil and water?
oil droplets are repelled by the hydrophilic part of the emulsifier and water molecules latch on.
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why do we cook food?
to improve texture and flavour, to make it easier to digest, to kill off microbes, some foods are poisonous when raw
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why do we cook eggs and meat?
their protein molecules change shape when heated. energy from cooking breaks chemical bonds giving the molecules different shape and the it then has a more edible texture
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why do we cook potatoes?
they are surrounded by a rigid cell wall made of cellulose. we can't digest cellulose but cooking the potato ruptures the cell wall and starch grains swell up making the potato softer.
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what is thermal decomposition?
its when a substance breaks down into simpler substances when heated.
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what is the word equation for thermal decomposition?
sodium hydrogencarbonate -> sodium carbonate + water + carbon dioxide
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how can you detect carbon dioxide?
by bubbling it through lime water as it turns it cloudy.
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what is used to usually make a perfume?
an ester(s)
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what is the word equation for esterification?
acid + alcohol -> water + ester
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what properties do perfumes need?
easily evaporates, non - toxic, doesn't react with water, doesn't irritate the skin, insoluble in water
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what are the forces like between solids?
there are strong forces of attraction between particles keeping them fixed. the particle don't move they only vibrate and the hotter the solid the more the particles vibrate
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what are the forces like between liquids?
there is some force of attraction between particles they tend to fix together. they don't keep a definite shape. the particles move in a random motion
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what are the forces like between gases?
there is no force of attraction between particles, they are free to move. they don't keep a specific shape or volume. particles constantly move
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why do we smell things?
because of volatility
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what is volatility?
how easily a liquid evaporates
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why do perfumes need to be quite volatile?
so they can evaporate enough for us to smell
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how do thermochromic pigments work?
they change colour when heated or cooled
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what are thermochromic paints used for?
baby products e.g spoon / bath toys so you know food or bath water isn't too hot, mood rings, mugs
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why do we mix thermochromic paints with other paints?
to give a wider rage of colour changes
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how do phosphorescent pigments work?
they absorb artificial or natural light and store that light energy in their molecules and then release the light over a certain period of time
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where are phosphorescent pigments used?
watches, emergency signs, decorations
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what did watch hands used to be made with?
radioactive pigments but these weren't safe
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what are plastics?
a long chain of molecules called polymers
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how are polymers formed?
when lots of small monomers join.
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what's the reaction called when monomers join together?
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what does polymerisation need to work?
a catalyst and high pressure
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what do monomers which make up additional polymers have?
a double covalent bond
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when are molecules unsaturated?
when they have at least one double covalent bond between carbon atoms
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when are molecules saturated?
when there is no double bond between carbon atoms
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what are unsaturated monomer molecules called?
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how does polymerisation work?
alkenes open up their double bonds and join to form polymer chains
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how do we name polymers?
it comes from the type of monomer it has been made from and then just stick the word poly infront e.g polypropene
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what is the plastic like if it has weak intermolecular forces?
the plastic can be stretched easily and has a low melting point
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what is the plastic like if it has strong intermolecular forces?
the plastic can't be stretched, has a higher melting point and can't be streched
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what are strong and rigid polymers used for?
plastic bottles
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what are light and stretchy polymers used for?
plastic bags and squeezy bottles
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what are PVC polymers used for?
rigid kind is used for window frames and the flexible kind is used for synthetic leather
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give examples of synthetic polymers.
nylon, PTFE
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what is gore tex made of
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how do we dispose of plastics?
recycling and re using them
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what are hydrocarbons?
hydrogen and carbon atoms
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what are hydrocarbons called?
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what are hydrocarbons used in?
fuel, plastics
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how are hydrocarbon molecules held together?
by strong covalent bonds
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how do you tell the difference between alkenes and alkanes?
you a substance to bromine water and the alkane won't decolourise
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why won't alkanes form into polymers?
because they have no double bonds to open up
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what is the formula for an alkane?
CnH2n+2 (2 is small)
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what order do the fraction go in when crude oil is separated?
LPG, petrol, naphtha, Paraffin, diesel, oil, bitumen
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what happens as the size of hydrocarbon molecules increase?
boiling point increases, less flamable, more viscous (don't flow so easily), less volitile
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how does fractional distillation work?
you can separate out a random mix of hydrocarbons into groups
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what are the two types of bond in crude oil?
strong covalent bonds between carbons and hydrocarbons within each hydrocarbon molecule + intermolecular forces of attraction between different hydrocarbon molecules
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what happens when crude oil is heated?
molecules are supplied with extra energy making them move more and can overcome intermolecular forces and go whizzing off as a gas
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what is cracking?
it turns long alkane molecules into smaller alkene molecules which are more useful
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what do you need for cracking?
lots of heat and a catalyst
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whats phase 1 of the evolution of the atmosphere?
volcanoes gave out steam and co2
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whats phase 2 of the evolution of the atmosphere?
green plants evolved and produced oxygen
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whats phase 3 of the evolution of the atmosphere?
ozone layer allows evolution of complex animals
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how does the carbon cycle work?
respiration, combustion and decay of plants and animals add carbon dioxide and remove oxygen from the air. photosynthesis then does the opposite. these processes should balance out but humans upset the natural carbon cycle and affected gas balence
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how does human activity affect the composition of the air?
as the population increases more carbon dioxide is given out. more people means more energy is needed so more fossil fuels are burnt = more carbon dioxide. deforestation happens stopping oxygen being released back into the earth.
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what is acid rain caused by?
sulfur dioxide and oxides of nitrogen
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what effect does acid rain have on earth?
it causes lakes to become acidic which kills fish and other plants. it corrodes limestone
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what effect does carbon monoxide have on your body?
it can stop your blood from carrying oxygen leading to fainting, comas or death
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what do catalytic converters do?
they reduce the amount of carbon monoxide and nitrogen oxides getting into the atmosphere
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Other cards in this set

Card 2


what are molecules?


atoms joined with other atoms

Card 3


what are compounds?


Preview of the front of card 3

Card 4


what do atoms form to make molecules or compounds?


Preview of the front of card 4

Card 5


what is involved when a bond is made?


Preview of the front of card 5
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