C6

Splitting up using electricity.  Break down/ Decompose a substance made of ions into simpler substances. 

Substance broken down is called an ELECTRODE.

Set up the electrical circuit for electrolysis with two electrodes which dip into electrolyte. One of the electrodes is connected to the positive terminal of a power supply, the other is connected to the negative

They normally make the electrodes out of an unreactive substance like graphite or platinum.  this is so they dont react with either the electrolyte or the products made during electrolysis. 

ANODE= POSITIVE

CATHODE=NEGATIVE

during electrolysis the positive charged ions move to the negative electrode and negative ions move to the positive electrode.

When the ions reach the electrodes, they can lose their charge and be deposited as elements.

Many ionic substances have a very high melting point which can make electrolysis difficult, even impossible.  But some ionic substances dissolve in water, and when this happens, the ions move freely.

NEGATIVELY CHARGED IONS LOOSE ELECTRONS TO BECOME NEUTRAL ATOMS.

POSITIVELY CHARGED IONS GAIN ELECTRONS TO FORM NEUTRAL ATOMS

GAINING ELECTRONS IS CALLED REDUCTION. this is because the lead ions are reduced.

LOOSING ELECTRONS IS CALLED OXIDATION.

REDOX=REDUCTION AND OXIDATION TAKING PLACE AT THE SAME TIME.

When electrolysis happens in water the less reactive element is usually produced at an electrode.

Chlorine gas is produced at the positive electrode. Hydrogen gas is produced at the negative electrode and a solution of sodium hyrdoxide is  also formed. 

sodium hydroxide  electrolysis hydrogen + chlorine+ sodium hydroxide solution.

chlorine used to clean swimming pools

Hydrogen used in the food industry. i.e reacting hydrogen with vegetable oils under pressure and with a catalyst to turn the oil into a soft spreadable solid.

Sodium hydroxide= make soap and paper. used to make bleach if combined with chlorine.

impurity found in copper are= gold, silver and platinum.  MUST BE REMOVED BECAUSE THEY AFFECT THE CONDUCTIVITY OF THE COPPER.

purify copper using electrolysis. A bar of impure copper is used as the anode + and a thin sheet of pure copper is the cathode - . Takes place in a solution containing copper ions.As the positive electrode, copper atoms are oxidised. they form copper ions and go into the solution: Cu (s) .... Cu2+ .....(aq) + 2e-Once we have purified the copper in the electrolytic cell it is removed, melted and then formed into bars or ingots.

electrolysis

electrolysing brine

Purfying copper