An electrostatic attraction between ions of opposite charge
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Features of a homologous series
M1) Similar chemical properties
M2) Trend in physical properties
M3) Same functional group
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Why any ionic compound has a high m.p./b.p.
M1) Attraction between ions is very strong
M2) Lots of ions in a giant lattice structure
M3) Therefore a lot of energy needed to break bonds
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Why an ionic solid does not conduct electricity bu
In solids no ions are free to move while in liquids ( molten/ aqueous) they can move / be mobile
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Metal bonding and structure
Positive ions are surrounded by a sea of delocalised electrons creating a strong electrostatic attraction between them
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Why does a metal conduct electricity?
It has a sea of delocalised electrons that are free to move
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Why are metals malleable?
Metal ions are arranged in layers that can slide over each other
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Why does a compound have a low b.p./m.p.?
It has weak intermolecular forces therefore little energy required to overcome
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Importance of cracking
M1) Greater supply of long chain hydrocarbons
M2) Higher demand for short chain hydrocarbons
M3) The alkenes produced can be used to make polymers/ plastic etc. Short chain - saturated - are used as fuels
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Bromine water with alkene and alkane
Alkene = Orange to colourless
Alkane = No change unless UV light is present, even then reaction is slow
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Observations of metals in acid ( specifically K an
M1) Solid dissolves/ dissapears
M2) Bubbles/ fizzing as gas forms
Specific to K and Na
M3) Sodium darts around and melts into a ball
M4) Potassium burns with a lilac flame
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Why do covalent compounds not conduct?
They have NO charged particles
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Why does increase in temprature result in a faster
Particles have more energy so there are more collisions per second, they have an energy greater than activation energy therefore more collisions per second
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What is a redox reaction?
M1) Both reduction and oxidation take place at the same time
M2) [Mention specific to the question what is reduced and oxidised]
M3) [Say why it is, e.g. A loses oxygen which is gained by B]
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Why would you repeat an experiment?
M1) To obtain concordant results
M2) To identify anomalous results
M3) To obtain a mean of concordant results
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What is a catalyst
M1) A substance that increases the rate of reaction
M2) And remains chemically unchanged/ not used up
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What does a catalyst do?
M1) Provides an alternative reaction pathway
M2) Which lowers the activation energy
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Lower temp or energy change than expected?
Often the reason is heat/ energy is lost to surroundings
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