Chemistry -Unit 1.

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  • Created by: lou
  • Created on: 24-05-15 15:19
What is the nucleus??
It's in the middle of the atom. It contains protons and neutrons. Protons are positively charged. Neutrons have no charge - they are neutral.
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What are electrons??
They move around the nucleus. They are negatively charged. they occupy shells around the nucleus.
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Number of protons equals the number of electrons.
Atoms have no charge overall. They are neutral. The charge on the electrons is the same size as the charge on the protons. If some electrons are added/removed, the atom then becomes charged and is therefore an ion.
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What are the electron shell rules??
Electrons always occupy shells. The lowest shell is always filled firsr. Only a certain numer of electrons fit in each sheel 2,8,8. Atoms are much happier when they have full outer shells, like the nobel gasses. Most atoms react to fill their shell.
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What is ionic bonding??
Between metals and non-metals. The metal atoms lose electrons to form positive ions and non-metals atoms gain electrons to form negative ions.
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What is covalent bonding??
Between non-metals. Eah atom shares an electron with another atom.
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What is limestone??
Mainly calicum carbonate.
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What happens when you heat limestone??
It thermally decomposes to make calcium oxide and carbon dioxide.
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What happens when calcium carbonate reacts with an acid??
It forms a calcium salt, carbon dioxide and water.
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What happens when you react calcium oxide with water??
You get calcium hydroxide.
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Wat other useful things can be made from limestone??
Powdered limestone is heated in a kiln with powdered clay to make cement. Cement cn be mixed with sand and water to make mortar. Mix cement with sand and aggregate to make concrete.
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Why is quarring bad??
Huge ugly holes which permanently damage the landscape. Blasting rocks aprt with explosives, lost of noise + dust. Destroys habitats. Pollution form lorries.
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Why is limestone good??
Houses and roads. Paints, dyes and medicines. Neutralises acidic soil. Provides people with jobs - boost the economy. Restoration is usually included. Widely avaliable, cheaper and quite easy to cut. Does not corrode.
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What is a metal ore??
A rock that conatins enough metal to make it worth while extracting it from the rock.
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How can metals be extracted from their ores??
Chemically or by reduction or by electrolysis.
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How can metals be extraced by reduction??
Metals below carbon in the reactivity series can be extracted byt reduction with carbon.
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How can electrolyss be used to get copper??
Electrons are pulled off copper atoms at the positive electrode, causing them to go into the solution as Cu2+ ions. Cu2+ ions near the negative electrode gain electrons and turn into copper atoms. The impurites are dropped at the positive electrode
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How can a displacement reaction be used to extract copper??
Scrap iron can be used to displace copper to form iron salt + copper.
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What is bioleaching??
Bacteria separate cooper from copper sulfide. Bacteria get energy from the bond between cooper and sulfur, separating out the copper from th ore in the process.
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What is phytomining??
Growing plants in soil that that contains copper. The copper gradually builds up in the leaves the planst as it can't be used. The plants cn be havested, dried, and burned in a furnace. The copper can be collected from the ash left in the furnace.
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How is metal extraction bad for the environment??
Causes noise, scarring of the landscape, loss of habitats, deep mine shafts can be dangerous and pollution.
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Why is it important to recylce metals??
Mining/extracting involves the use of a lot of fossil fuels which are running out and they contribute to acid rain/ global dimming/warming. Recycling metal uses a fraction of energy compared to extracting new metals. Only a finite amount of metals.
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Name a metal which can be extracted from it ore by reduction with carbon??
Any below carbonin the reactivity series.
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Why is electrolysis so expensive??
It uses a lot of energy.
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What are the basic metal properties??
Strong, hard to break - but can be bent of hammered into different shapes. They are great at conducting heat. They conduct electricity well.
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What everyday uses to metals have??
Their strength and bendability makes them handy for bridges + car bodies. Saucepan base - heat travels through. Electrical wires - conductive.
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What bad properites to metals have??
Corrode. Metal fatigue which leads to them breaking.
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What can copper be used for??
Wires - good conductor, hard, strong, can be bent and does not react with water.
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What is an alloy??
A mixture of metals or a mixture of a metal and a non-metal.
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Which are harder, pure metals or alloys??
Alloys.
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Give two properites of why aluminium can be used to make an aircraft.
Corrison-resitant and it has a low density.
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Other cards in this set

Card 2

Front

What are electrons??

Back

They move around the nucleus. They are negatively charged. they occupy shells around the nucleus.

Card 3

Front

Number of protons equals the number of electrons.

Back

Preview of the front of card 3

Card 4

Front

What are the electron shell rules??

Back

Preview of the front of card 4

Card 5

Front

What is ionic bonding??

Back

Preview of the front of card 5
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