chemistry

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How can insoluble salts be made?
By mixing appropriate solutions of ions.
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What is formed when making an insoluble salt?
A solid precipitate.
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What is precipitation used for?
To remove unwanted ions from solutions, e.g, treating drinking water or effluent.
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What is electrolysis?
Electrolysis is the process by which ionic substances are decomposed (broken down) into simpler substances when an electric current is passed through them.
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What is the substance you pass the electricity through in electrolysis called?
The electrolyte.
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How must the ions be for electrolysis to work?
For electrolysis to work, the ions must be free to move. Ions are free to move when an ionic substance is dissolved in water or when melted.
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What happens in electrolysis?
Positively charged ions move to the negative electrode during electrolysis. They receive electrons and are reduced. Negatively charged ions move to the positive electrode during electrolysis. They lose electrons and are oxidised.
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What happens to the electrons in oxidation?
Electrons are lost.
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What happens to the electrons in reduction?
Electrons are gained.
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What is electrolysis used for?
To electro-plate objects with copper, silver, or gold.
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How does electro-plating work?
The negative electrode should be the object that is to be electroplated. The positive electrode should be the metal that you want to coat the object with. The electrolyte should be a solution of the coating metal, such as its metal nitrate or sulfate
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Why is aluminium expensive?
Because there is a lot of electricity used up in the extraction process which is done by electrolysis.
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Why does the use of cryolite reduce some of the energy costs involved in extracting aluminium?
Because it makes the aluminium melt at lower temperatures.
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How is aluminium extracted?
First the aluminium oxide must be melted so that electricity can pass through it. Aluminium metal forms at the negative electrode and sinks to the bottom of the tank, where it is tapped off. Oxygen forms at the positive electrodes.
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When extracting aluminium, what forms at the negative electrode?
Aluminum metal.
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When extracting aluminium, what forms at the positive electrode?
Oxygen.
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Why is extracting aluminium expensive?
Because there is a lot of electricity used, because it melts at high temperatures, and because the oxygen that forms at the positive electrode reacts with the carbon that the electrode is made of, forming carbon dioxide so the electrodes are replaced
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Other cards in this set

Card 2

Front

What is formed when making an insoluble salt?

Back

A solid precipitate.

Card 3

Front

What is precipitation used for?

Back

Preview of the front of card 3

Card 4

Front

What is electrolysis?

Back

Preview of the front of card 4

Card 5

Front

What is the substance you pass the electricity through in electrolysis called?

Back

Preview of the front of card 5
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