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28 Cards in this Set
- Front
- Back
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What forms at the Anode and the cathode |
Anode anions non metals Cathode cations metals or hydrogen |
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How much products is made during electrolysis |
Directly proportional to current used and time taken |
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Describe a hydrogen fuel cell and how it works |
The reaction of oxygen and hydrogen releases energy to produce voltage |
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Advantages and Disadvantages of fuel cells |
Water vapour only waste No CO2 emissions Large potential source of fuel Hydrogen production involves fossil fuels Use poisonous catalysts that need proper disposal |
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What is an oxidising or reducing agent |
Oxidising agent remove electrons from substances so it can react with oxygen Reducing agent gives electrons |
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How to prevent rust |
Coat with oil or grease Zinc - galvanising oxidises instead of the iron sacrificial protection Tin - less reactive than iron |
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What is fermentation |
Using yeast to convert glucose to CO2 and ethanol as long as there is no oxygen present Ethanol is separated from the mixture by fractional distillation as it has a lower boiling point than water
Need temperatures above 25 but below 50 If oxygen reacts with it it oxidises and forms vinegar
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Fermentation of sugar vs hydration of ethene for making ethanol |
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Molecular formula of alcohol |
CnH2n+1OH |
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How do CFCs destroy the ozone layer |
CCl3F (UV light ) .CCl2F + .Cl .Cl + O3 = .ClO + O2 .ClO + O3 = 2O2 + Cl This causes a chain reaction destroying lots of ozone The 2O3 becomes 3O2 turning ozone into oxygen |
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Properties and replacement for CFCs |
Low boiling point Insoluble in water Chemically inert HFCs do not contain chlorine atoms so they don't damage the ozone |
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Types of hardness |
Permanent caused by dissolved calcium sulfate Temporary causes by dissolved calcium hydrogen carbonate |
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Difference between hard and soft water |
Concentration of calcium and magnesium ions and how hard it is to form a lather |
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How to remove temporary hardness |
Boil it, decomposes into calcium carbonate water and CO |
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Why are weak acids used as limescale removers |
Weak acids don't react woth the metal of the equipment but do with the limescale |
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Removing hardness equation |
Calcium carbon + citric acid = calcium citrate + water + carbon dioxide |
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How does washing soda remove hardness |
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How do ion exchange resins work |
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What is an ester linkage |
Carob attached to two oxygen with a double bond |
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Why are saturated fats unhealthy and unsaturated fats healthy |
They can raise cholesterol levels which may block arteries leading to a stroke Unsaturated fats contain omega 3 |
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Describe the two types of emulsion |
Oil in water - milk Water in oil - butter |
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What is saponification |
Hydrolysis reaction ester linkage is broken Fat + sodium hydroxide = glycerol + soap |
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What is a detergent |
Hydrophobic tail and hydrophilic head able to lather in hard water but can damage delicates |
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What is a biological powder |
A washing powder that uses enzymes Must be used at low temperatures to avoid denaturing meaning that less energy is required and more fabrics can be cleaned |
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Ingredients of washing powders and washing liquids |
Washing powder Active detergent Bleaches destroys dye Optical brighteners Water softners Enzymes remove food stains
Washing liquids Active detergent Water makes solutions thinner and less viscous Colouring agent and fragrance Rinse agent helps water drain |
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How does dry cleaning work |
Solvent such as tetrachloroethene is washed with the clothes Rinsed and then dried in the warm air Used when water would damage the clothing or wouldn't remove the stain |
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Why do we use molten instead of solid ionic compounds in electrolysis |
The ions are free to move |
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Advantages of fuel cells on space crafts |
Light weight compact |
