Salts and electrolysis

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  • Created by: Sam Evans
  • Created on: 02-03-15 20:28
What type of substance is sodium hydroxide?
An alkali
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What type of reaction happens?
Neutralisation
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Why is an indicator used to show when the reaction is complete?
There is no visible change and it will show when the pH is 7
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Write a word equation for the reaction
nitric acid + sodium hydroxide -> sodium nitrate + water
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Describe the main steps to make zinc sulphate crystals from zinc oxide and dilute sulphuric acid.
Add zinc oxide, a little at a time, to dilute sulphuric acid, until there is an excess, filter off the excess, evaporate some of the water, leave to cool and crystallise.
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Describe how you could make some insoluble lead sulphate from solutions of lead nitrate and sodium sulphate
Mix the two solutions, filter the mixture or leave to settle and decant or centrifuge and decant to separate the solid (precipitate). Then wash with distilled water and dry.
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Why are some items of jewellery made of gold-plated nickel?
Less expensive than pure gold, to improve appearance, so they do not corrode (or cause allergic reactions)
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Name the products when sodium chloride solution is electrolysed and give one use for each.
Hydrogen, chlorine and sodium hydroxide. A use for each, e.g hydrogen: to make hydrochloric acid, margarine manufacturer, fuel; chlorine: to make bleach, plastics; sodium hydroxide: to make soap, paper, as a cleaning agent, (ovens/drains)
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Why is manufacturing aluminium an expensive process.
It needs large amounts of electricity, high temperatures to melt the aluminium oxide.
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Why is cryolite used in the process to make aluminium?
To lower the melting/operating temperature (of the electrolyte)
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Explain as fully as you can what happens at the electrodes when molten sodium chloride is electrolysed.
At the negative electrode: sodium ions gain electrons, are reduced, to sodium atoms/metal. At the positive electrode: chloride ions lose electrons, are oxidised, to chlorine atoms, which form chlorine chlorine molecules/gas.
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Write half equations for the reactions at the electrodes when magnesium chloride solution MgCl2 (aq) is electrolysed using carbon electrodes
At the negative electrode: At the positive electrode:
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Other cards in this set

Card 2

Front

What type of reaction happens?

Back

Neutralisation

Card 3

Front

Why is an indicator used to show when the reaction is complete?

Back

Preview of the front of card 3

Card 4

Front

Write a word equation for the reaction

Back

Preview of the front of card 4

Card 5

Front

Describe the main steps to make zinc sulphate crystals from zinc oxide and dilute sulphuric acid.

Back

Preview of the front of card 5
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