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  • Created by: Bonnie
  • Created on: 07-06-14 13:54
What is rate of reaction?
Time taken between starting and stopping
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What does reaction measure?
Measures rate of disappearance of reactant
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What is an example of a slow reaction?
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What is an example of a fast reaction?
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An example to suggest?
Magnesium and Hydrochloric Acid (Mg + 2HCl -> MgCl2 + H2
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How to do this...
1) Clean magnesium ribbon 2) Place in test tube 3) Set up apparatus 4) Shake flask to mix 5) Start stopwatch 6) Record volume of hydrogen in gas syringe every half minute
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Methods to measure rates
Colour changes, temperature changes, formation of precipitate and time taken to react
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Amount of product formed is..
directly proportional with amount of limiting reactant
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What do manufactures use powder instead of lumps?
Powder has larger surface area as particles that were inside the lump become exploded and crushed.
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What are explosions?
Very fast reactions in which a large volume of hot gases are released in a short amount of time
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What is an example of an explosion?
Hydrogen beings ignoted (2H -> O(2) + 2H(2)O
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What is the collision theory?
The principle that reaction only occurs when particles collide with each other, and that reactions have sufficient minimum energy called Activation Energy
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What is a catalyst?
Substance which increases that rate, not yield. And remains unchanged throughout reaction.
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Why is a catalyst used?
To reduce costs.
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What is an example of a catalyst?
Iron in haber process, hydrogen peroxide in bleach
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What does A(r) mean?
Relative atomic mass
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What does M(r) mean?
Relative formula mass
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Why is mass conserved?
No atoms are created or detroyed
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Equation for percentage yield?
(actual yield / predicted yield) x 100
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What does increasing the amount of reactants do?
Increases amount of product produced, but percentage yield stays the same under the same conditions
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Why will percentage yield never be 100%?
Reaction may not go to completion because it is reversible, some product may not be lost when it being prepared, reactants react differently
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Why is it important in industry?
To avoid wasting reactant (reducing costs)
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Equation for atom economy?
(m(r) of desired products / total m(r) of all products) x 100
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Why is waste bad in industry?
Have to be disposed of, contributes to pollution, raises costs of production, make ineffective use of resources
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What does low atom economy mean?
Low atom economy means few atoms in reactants have been converted into the desired product
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What is an exothermic reaction?
Energy is transferred into the surroundings (energy is released) (temperature rise) (bond making)
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What is an endothermic reaction?
Energy is taken from surroundings (energy absorbed) (temperature fall)
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Examples of exothermic reactions?
combustion, oxidation reactions, neutralisation reactions
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Examples of endothermic reactions?
photosynthesis, thermal decomposition
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What is calorimetry?
Method used to measure the energy transferred in chemical reactions
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1) Fuel is put into spirit burner, then weighed. 2) Calorimeter is filled with known mass of water. 3) Temperature of water is measured. 4) Wick of spirit burner is lit so flame warms up water 5) Spirit burner weight and water temperature is recorded
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Equation for energy transferred.
Mass of water heated x Temp change x 4.2
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Equation for energy/gram
Energy transferred / mass of fuel burnt
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What are the variables in calorimetry?
Volume of water used, starting temperature, height of calorimeter from spirit burner
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Examples of continuous processes?
Ammonia (haber process), sulfuric acid, chlorine
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Examples of batch processes?
Pharmaceuticals, wine, specialty chemicals
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What are factors that affect cost in r&d?
Raw materials, development, research and testing, labour costs, energy costs, marketing
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What is purity tested by?
Thin layer chromotography
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Characteristics of diamond?
Insoluble in water, lustrous, colourless and clear, high melting point, does not conduct electricity
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Why does diamond not conduct?
Electrons are used in covalent bonds
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What is diamond used for?
Cutting tools, as it is hard and has a high melting point. Jewellery, as it is lustrous.
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Characteristics of graphite?
Black, lustrous, opaque, high melting point, soft and slippery, can conduct electricity.
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Why can graphite conduct?
Carbon atoms are in layers therefore there are delocalized electrions
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What are graphites and diamonds ...... of carbon?
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What does allotropes mean?
Different forms of the same element in the same physical state
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Card 2


What does reaction measure?


Measures rate of disappearance of reactant

Card 3


What is an example of a slow reaction?


Preview of the front of card 3

Card 4


What is an example of a fast reaction?


Preview of the front of card 4

Card 5


An example to suggest?


Preview of the front of card 5
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