C6

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  • Created by: Emily
  • Created on: 10-06-13 17:06
what are the ions like in a solid and substance?
solid- fixed and can't move substance- molten or in solution that they are free to move in
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what are the positive ions and negative and where do they discharge?
pos- cations - cathode neg- anions - anode
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what is the amount of substance made in electrolysis determined by?
the size of the current and the length of time it flows for
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when is more substance made?
larger current or the current flows for a longer period of time
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what two factors affect the amount of substance made during electrolysis?
temperature and pressure
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what happens when you test for hydrogen and oxygen gas?
hydrogen- lighted splint causes a 'pop' oxygen- glowing splint it re-lit
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what are some disadvantages and advantages of using fuel cells?
A- less pollution, efficient and are compact D- often contain poisonous catalysts which have to carefully be disposed of and to make hydrogen fuel energy is needed- may come from burning of fossil fuels
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what is the reaction called between hydrogen and oxygen?
exothermic- releases energy
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what happens when a hydrogen reacts with oxygen in a fuel cell?
makes an electric current- energy used to create potential difference
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how can you prevent rusting?
galvanising- coating iron or steel with zinc, stops water and oxygen reaching iron Alloying, tin plating- acts as a barrier between iron, air and water and sacrificial protection- placing a more reactive metal in contact with the iron or steel
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what kind of reaction is a displacement reaction?
redox- metal ion is reduced by gaining electrons and metal atom is oxidised by losing electrons
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what does OIL RIG stand for?
oxidation is lost and reduction is gained
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what are alcohols?
family of organic compounds containing hydrogen, carbon and oxygen
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what are some uses of ethanol?
to make alcoholic drinks, to make solvents and as fuel for cars
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what can ethanol be made by?
fermentation- yeast is used to ferment glucose solution
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how can pure ethanol be extracted from fermentation mixture?
by fractional distillation
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why does the fermentation mixture have to be kept at 25-50c (optimum temp)?
if it falls below, yeast become inactive/ rises above the enzymes denature
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is the chemical reaction to turn ethene into ethanol reversible and what's the equation?
yes it is, the equation is: ethene ↔ ethanol
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how can ethene be hydrated to make ethanol?
passing it over a heated phosphoric acid catalyst with steam (industrial use/non-renewable)
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why is the ethanol made by hydration non-renewable?
because it would have been made by cracking components
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what is quicker hydration or fermentation?
hydration- continuous process- available in large quantities fermentation- slow batch process and is expensive
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what is the atom economy and yield like in fermentation and hydration?
hydration has 100% atom economy but fermentation has a higher percentage yield
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where is ozone found?
found in a layer high up in the atmosphere- called the stratosphere
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what are chlorofluorocarbons (CFC's)?
organic molecules that contain chlorine fluorine and carbon- used as refrigerants and in aerosols
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why were CFC's used in aerosols?
low boiling point, insoluble in water and they are unreactive
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what are used as an alternative to CFC's?
hydrocarbons (alkanes) because they don't damage the ozone layer and are safer
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harmful UV light that reaches the Earth can cause..
increased aging of skin and risk of sunburn, skin cancers and increased risk of cataracts
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what happens when a CFC molecule is hit by a UV light?
a chlorine atom is produced, called a radical
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what is soft water and what is hard water?
soft- lathers well with soap hard- doesn't lather with soap
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what is hardness in the water caused by?
calcium and magnesium ions from dissolved salts
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what is the difference between temporary and permanent hardness?
permanent- dissolved by calcium sulfate- can't be destroyed by boiling temporarily- forms when rainwater comes into contact with rock that contains calcium carbonate, can be removed by boiling
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what happens when rainwater contains dissolved carbon dioxide?
it makes it slightly acidic- when rainwater reacts with rock it makes soluble calcium hydrogen carbonate- temp hardness
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what does insoluble calcium carbonate deposit as?
limescale
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what two methods can be used to remove permanent hardness from water?
adding washing soda or passing water through an ion-exchange system
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why are the calcium and magnesium ions removed from the water?
because they form precipitates of insoluble calcium carbonate and magnesium carbonate
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describe un sat and sat bonds?
sat- single bonds un sat- double bonds
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what can you use to test if un sat or sat?
bromine water- un sat= change from orange to colourless sat- remain orange
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what can you add to water and oil to help mix them?
emulsion- small droplets disperse in the water
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what is saponification?
the process used to make soap by reacting veg oil with hot sodium hydroxide
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what are the main components of washing powder?
active detergent- cleaning bleach- removes stains water softner- softens hard water optical brightner- makes whites appear brighter enzymes- break up food in low temps
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what is the solvent, solute and solution when washing clothes?
solvent- water washing powder- solute resulting mixture- solution
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what forces to molecules making up a stain like?
weak intermolecular forces
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what kind of head and tail does a detergent molecule have?
hydrophilic head and a hydrophobic tail
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Other cards in this set

Card 2

Front

what are the positive ions and negative and where do they discharge?

Back

pos- cations - cathode neg- anions - anode

Card 3

Front

what is the amount of substance made in electrolysis determined by?

Back

Preview of the front of card 3

Card 4

Front

when is more substance made?

Back

Preview of the front of card 4

Card 5

Front

what two factors affect the amount of substance made during electrolysis?

Back

Preview of the front of card 5
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