Introduction to electrolysis Flashcards
What is electrolysis?
In electrolysis you use an electricity to break down and ionic compound.
What is an electrolyte?
The compound that is broken down by electrolysis.
What are the two electrodes called? (give the charge)
1) Anode (positive)
2) Cathode (negative)
What are the electrodes made out of?
Are often made out of an unreactive or inert substance such as graphite.
Why are electrodes made out of an inert substance?
So that the electrodes do not react with the electrolyte or with the products made in electrolysis.
What is the rule between negative and positive charges in electrolysis?
During electrolysis, positively charged ions move to the cathode. At the same time, the negative ions move to the anode as opposites attract.
Explain how electricity breaks down zinc chloride into zinc and chloride.
1) Zinc chloride is an ionic compound. Ionic compounds do not conduct electricity when they are solid, as their ions are in fixed positions in their lattice.
2) Once an ionic compound is melted the ions are free to move around with the hot liquid and carry their charge towards the electrodes.
3) The positive zinc ions move towards the cathode.
4) Negatively charged chloride ions move towards the anode.
Why is it more difficult to predict what will be formed when doing electrolysis using a solution?
Water also forms ions, so the products at each electrode are not exactly what you expect. Only metals of very low reactivity, below hydrogen are deposited from their aqueous solutions in electrolysis.
