13. Electrolysis Flashcards
What is the definition of electrolysis?
Electrolysis is the spitting up of a compound in solution or molten into the two elements
What must electrolytes contain to be able to be used?
Free electrons so they can conduct electricity
Where do negative ions move?
To the positive electrode (The Anode) and lose electrons (oxidation)
Where do the positive ions go to?
To the negative electrode (The Cathode) and gains electrons (Reduction)
What affects the product formed in electrolysis?
The reactivity of the substances
At cathode what will form?
The less reactive substance will form, if metal ions and H+ ions are present, hydrogen will form unless the metal is less reactive
Electrolysis of Sodium Chloride solution
At the Cathode: Two Hydrogen ions accept two electrons to become one Hydrogen molecule
At the Anode: Two Chloride ions lose they electrons and become one Chlorine molecule
The sodium ions stay in solution because they’re more reactive than Hydrogen. Hydroxide ions from water left behind means that Sodium Hydroxide is left behind
What is one use of Chlorine gas?
In the production of Chlorine gas
What is one use of Sodium Hydroxide?
Used to make soap
What is on of the main ores of Aluminium?
Bauxite
Why is cryolite used for electrolysis of Aluminium instead of Aluminium Oxide?
It brings the melting temperature down to about 900’C which makes it cheaper and easier
Electrolysis of Aluminium from cryolite
Aluminium is formed at the Negative Cathode
Oxygen forms at the positive Anode
The electrodes are made of Carbon and the oxygen reacts with the electrode to produce Carbon Dioxide, this means occasionally they must be replace as “eaten away
Reasons for electroplating objects
Improve the appearance
Make them more durable
Make them resistant to corrosion
So they can conduct electricty
Electroplating
Place the object you want to plate at the Cathode
Place the pure metal on the Anode
Make sure the electrolyte contains ions of the plating metal
