C5 - Electricity and chemistry

Positive is Anode, Negative Is Cathode

the process of splitting an ionic compound when molten or aqueous solution by the passage of electricity

free to move around in the solution

rod that conducts electricity (they come in pairs of Pos and neg)

ionic compounds dissolved in water to make a solution that conducts electricity

By using a complete circuit which shows whether a light bulb will glow or not. Electrolytes will make the light bulb glow Non-electrolytes will do nothing

Oppositely attract Positive ions go to negative electrode (cathode) Negative ions go to positive electrode (anode)

transferred to form elements. E.g if Cu2+ ions in a solution move to the cathode due to voltage applied, when they touch the cathode each Cu2+ will gain 2 electrons and form a copper metal

When ionic compounds are dissolved in a solution or turned molten the ions are free to move. The solution can then conduct electricity and will attract to a certain electrode.

When a voltage is applied across an electrolyte, the charged ions are attracted to the oppositely charged electrodes. Copper ions (Cu2+) are positively charged, so will move towards the cathode (negative electrode). When the copper ions (Cu2+) touch the cathode, each ion will gain 2 electrons, forming copper metal: Cu2+(aq) + 2e- → Cu(s)

Usually made out of carbon or platinum as they are inert meaning they won’t undergo the chemical change during electrolysis.

When PbBr2 is melted the ions are free to move. The voltage is applied and the positive lead ions move to the cathode The negative bromide ions move to the anode The products of the electrolysis are the elements bromine and lead as the ions gain or loss their electrons to form elements. Silvery deposits of lead form near the cathode and brown bromine vapor form near the anode to show electrolysis occurred.

Pb2+ + 2e- ==> Pb 2Br- ==> Br2 + 2e-

Water molecules in the solution split up to form H+ ions and OH- ions. What is formed at the cathode: If the metal is more reactive than hydrogen, hydrogen is produced. If the metal is less reactive than hydrogen, the metal is produced. What is formed at the anode: If halide ions are present, the halogens form If halide ions are absent, oxygen forms

Ionic compound NaCl dissolves in water. Sodium and chloride ions separate and are free to move. Hydrogen and hydroxide ions also are free to move separated from the water. Sodium is more reactive than hydrogen so, hydrogen ions are discharged and form as molecules at the cathode. The sodium ions stay in the solution Since there is a presence of a halide ion (chloride), chlorine ions discharge and form chlorine molecules at the anode. OH- ions stay in the solution BaCl ==> Na+ + Cl- H2O <==> H+ + OH-

the process in which water breaks up and forms ions

When NaCl solution is dilute OH- ions form at the anode to produce oxygen When NaCl solution is concentrated Cl- ions form at the anode to produce chlorine

Hydrogen will form at cathode as it is less reactive than magnesium

copper and oxygen are produced. Copper forms as a reddish brown coating on the cathode Oxygen forms as colorless gas bubbles on the anode The solution becomes paler blue as copper ions are discharged

Cu2+ ions gain two electrons and are discharged at the cathode. Copper atoms are formed and the mass of the electrode increases At the node copper atoms lose two electrons and Cu2+ ions are formed. The anode dissolves and loses mass

because rate of production of cu2+ ions at the anode is exactly balanced by the rate of removal of Cu2+ ions at the cathode. It is an important reaction in refining copper

Copper is extracted from its ore by reduction with carbon but the copper produced is not pure enough for its uses like electrical cables. It can be purified using electrolysis with copper electrodes

electrolysis to coat an object with a thin film of metal

a good way of improving appearance of metals and preventing their corrosion