C5 Revision

  • Created by: ElishaG
  • Created on: 14-06-16 16:43
What is dry air a mixture of?
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What are the percentages of the 4 main elements in the air?
Nitrogen-78%.Oxygen-21%.Argon-1%.Carbon dioxide-0.04%.
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Give two examples of molecular substances.
Water(H2O). Carbon Dioxide (CO2).
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How are the atoms in the molecules held together?
By strong covalent bonds.
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What are the forces of attraction like between the molecules?What does this mean?
Very weak.Means little bit of energy needed to overcome weak forces.
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What are the melting nd boiling points of molecules like?
Low melting and boiling points as force of attraction is weak.
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What are molecules usually like at room temperature?
Liquids or gases.
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Why don't pure molecular substances conduct electricity?
Their molecules aren't charged-no free electrons or ions.
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What kind of elements are mostly molecular?
Non-metals and compounds formed from non-metals.
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What are covalent bonds between?What do they do?
Non-metals. They share electrons to have full outer shell.
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What does each covalent bond provide?
One extra shared electron for each atom.
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Why the do the atoms bond?
Due to electrostatic attraction between positive electron and negative electrons.
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What is the formula for methane?
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What does the Earth's hydrosphere consist of?
Oceans,seas,rivers,lakes etc. and things dissolved in the water.
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Why is the sea salty?
Lots of ionic compounds(salts) dissolved in water.
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What are 3 examples of salt and their formulas?
Sodium chloride NaCl. Magnesium chloride MgCl. Potassium bromide KBr.
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What are ionic compounds made of?
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What are ions with opposite charges like?
Strongly attracted to each other-massive lattice of ions builds up.
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What bonds are between all ions?
Chemical bonds called ionic bonds.
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What is a single crystal of salt?
One giant ionic lattice.
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What are the forces of attraction like between ions in an ionic compound?
Very strong- takes lot of energy to overcome forces.
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What are the melting and boiling points like for ionic compound?What are they like at room temperature?
High melting and boiling points.Solid at room temperature.
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What is an ionic compound like when it is dissolved or melts?
Ions separate and are free to move, can carry electric current.
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What is an ionic compound like when it is solid?
Electrons aren't free to move so they don't conduct electricity.
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What can flame tests be used for?
To detect and identify different ions.
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What colour flame does Sodium give?
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What colour flame does potassium give?
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What colour flame does Calcium give?
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What colour flame does Copper give?
Blue/green flame.
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What is a precipitation reaction?
When 2 solutions react to form an insoluble solid compound(a precipitate).
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What does an ionic equation show?
The useful parts of the reaction.
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What does hydrochloric acid help us to detect?How?
Carbonates. They will fizz as they give off carbon dioxide.
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How can you test for carbon dioxide?
Use limewater. Carbon dioxide turns limewater cloudy-need to bubble gas through test tube of limewater, if water goes cloudy there is a carbonate ion.
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How do you test for sulfates?
Add dilute hydrochloric acid then barium chloride solution-if precipitate is white, it was a sulfate.
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How do you identify a halide ion?
Add dilute nitric acid then silver nitrate solution.
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What colour precipitate does chlorine have?
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What colour precipitate does bromide have?
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What colour precipitate does iodide have?
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What parts of the Earth make up the lithosphere?
Crust and part of mantle.
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What is the lithosphere made up of?
Mixture of minerals, often contain silicon,oxygen and aluminium.
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What mineral does limestone contain?
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What mineral does sandstone contain?
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What are 2 giant covalent structures?What element are they made of?
Graphite and diamond. Made of carbon.
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Describe diamond.
1)Four covalent bonds.2)Hardest natural substance.3)Strong covalent bonds-high melting+boiling points.4)Doesn't conduct electricity-no free electrons, even when molten.5)Insoluble in water.
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What are uses of diamond?
Jewellery, drill bits, blades.
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Describe graphite.
1)3 covalent bonds-sheets of electrons that slide over each other.2)High melting and boiling point-lots of energy to break.3)Conducts electricity as there's free electrons.
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What are uses of graphite?
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What is another giant covalent structure?What is it made of?
Silicone dioxide. Made of silicon and oxygen.
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Describe silicon dioxide.
1)AKA silica, what sand is made of.2)Each sand grain is one giant structure of silicon and oxygen.3)Similar structure to diamond, similar properties (high M+B points and doesn't conduct electricity).
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What are rocks made of?
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What are minerals?
Solid elements and compounds.
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What are metal ores?
Rocks that contain minerals that metals can be extracted from.
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What is the ore usually?
An oxide of the metal.
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Why do large amounts of ore need to be mined for some metals?
Only a small percentage is in each ore.E.g. copper ores contain 1% copper.
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What kind of metals are just found as the metals themselves?Give an example.
Unreactive metals. E.g. gold.
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Why are some metals harder to extract?Give an example.
Because they are more reactive.E.g. sodium.
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What is a common way of extracting metals?
Reduction using carbon or carbon monoxide.
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What does reduction mean?
When the metal oxide loses its oxygen.
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What does oxidation mean?
When carbon gains the oxygen.
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What kinds of metals can be extracted by reduction?Why?
Metals less reactive than carbon.Because carbon can only take oxygen away from metals less reactive than itself.
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How are metals more reactive than carbon extracted?
By electrolysis.
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What is electrolysis?
The decomposition of a substance using electricity.
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Why is a liquid needed in electrolysis?
To conduct electricity(called electrolyte).
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What are the electrolytes?
Usually free ions dissolved in water(e.g. dissolved salts) or molten ionic compounds.
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What allows the whole process to work?
The free electrons.
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Where are the electrons taken away from in electrolysis?
The ions at the positive electrode.
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Where do thy electrons go?
To other ions at the negative electrode.
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What happens to ions when thy gain or lose electrons?
They become atoms or molecules.
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What is the main ore of aluminium?What does it contain?
Bauxite. Contains Aluminium Oxide (Al2O3).
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Why does molten aluminium conduct electricity?
Because it has free ions.
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Which ions are attracted to the negative electrode?What happens there?
Positive Al(3+) ions. At electrode picks up 3 electrons and turns into aluminium atoms-sink to bottom.
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Which ions are attracted to the positive electrode?What happens there?
Negative O(2-) ions. At positive electrode, loses 2 electrons and combine with each other to form O2 molecules.
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What happens at the negative electrode in electrolysis of aluminium>
Reduction and gain of electrons.
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What happens at the positive electrode in electrolysis of aluminium.
Oxidation and loss of electrons.
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What do metals consist of?
A giant structure.
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What do metallic bonds involve?
All of the free electrons- which produce all the properties of metals.
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Where do the free electrons come from?
The outer shell of every metal atom in the structure.
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How are metal ions held together.
Positively charged metal ions are held together in a crystal of free electrons that can move.
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Give 3 properties of metals.
1)Electrical and heat conductors.2)Strong and malleable.3)High melting and boiling points.
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Explain why metals are good electrical and heat conductors.Give examples.
Free electrons carry heat and electrical currents through material.E.g. saucepan base and electrical wiring.
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Explain why most metals are strong and malleable. Give uses.
Metallic bonds mean metals have high tensile strength.Layers of atoms slide over each other,which makes them malleable.E.g. can be hammered or rolled into flat sheets.Bridges and car bodies.
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Explain why most metals have high melting and boiling points.Why is this useful/
Metallic bonds very strong, lots of energy needed to break them.Useful as saucepan or bridges won't melt when it's hot.
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Ores are finite resources-what does this mean?
There is a limited amount of them.
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Why is mining metal ores good?
1)Useful products made.2)Provides locals with jobs.3)Brings money to area.4)Transport and health can be improved.
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Why is mining metal ores a bad thing?
1)Bad for environment- uses lot of energy,ruins landscape and destroys habitat.2)Noise,dust and pollution due to more traffic.3)Deep mine shafts dangerous when abandoned.
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True or False- mining metals doesn't use much energy?
False- Uses lots of energy, comes from burning fossil fuels.
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Why is it important to conserve fossil fuels?
1)Fossil fuels running out.2)Burning them contributes to acid rain,global dimming and climate change.
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Why should we recycle metals?
1)Recycling uses small fraction of energy needed to mine and extract new metal.2)Saves money.3)Recycling conserves finite resources.4)Cuts down on landfill rubbish.
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What would the UK be like if all aluminium cans were recycled?
14 million fewer dustbins of waste each year.
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Which kind of metal is the most cost-effective to recycle?
Aluminum- save 95% of energy,4 kg of ore, lot of waste.
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Other cards in this set

Card 2


What are the percentages of the 4 main elements in the air?


Nitrogen-78%.Oxygen-21%.Argon-1%.Carbon dioxide-0.04%.

Card 3


Give two examples of molecular substances.


Preview of the front of card 3

Card 4


How are the atoms in the molecules held together?


Preview of the front of card 4

Card 5


What are the forces of attraction like between the molecules?What does this mean?


Preview of the front of card 5
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