Topic 6 - Electrolysis Flashcards
In an electrical circuit for electrolysis, how many electrodes are there?
2
What’s the name given to the positive electrode?
Anode.
What’s the name given to the negative electrode?
Cathode.
The electrodes are made of what kind of substance?
An inert / unreactive substance.
When ions lose their charge, what do they become? What is the name for this process?
They become atoms or elements, the name of this process is discharging.
If I have a compound Zinc Chloride, formula ZnCl2, which of the elements in this compound will go to the anode?
Chlorine, as it is negatively charged and is attracted to lose electrons.
If I have the compound Zinc Chloride, formula ZnCl2, which of the elements in this compound will go to the cathode?
Zinc, as it is positively charged and is attracted to gain electrons.
What is the name given to the loss of electrons (by electrolysis)?
Oxidation.
What is the name given to the gain of electrons (by electrolysis)?
Reduction.
Complete the half equation to represent positively charged Lead ions becoming atoms. Pb2+ + ____ ——-> Pb
2e-
As electrons are gained to make lead ions into atoms.
Complete the half equation representing negatively charged Bromine ions becoming atoms.
______ ————> Br2 + 2e-
2Br-
The bromine ions have clearly lost 2 electrons and thus you need two negatively charged bromine ions.
In a normal glass of water, roughly what percentage of molecules can ionise?
Around 1% of molecules.
Why can’t compounds separate as solids?
They do not have the energy to separate into ions.
How do we separate compounds to form ions in electrolysis?
By melting the compound or dissolving it in water.
What is the rule for discharging ions at the cathode?
The least reactive element out of Hydrogen and the positively charged ion you are electrolysing becomes discharged.
