Electrochemistry
What is an electrolyte?
This is a liquid that conducts electricity due to the presence of ions.
What do you call negative ions and which electrode do they go to?
Anions
Anode
What is the name of the ore from which aluminium is extracted?
Bauxite
What ore is iron extracted from?
Hematite
What is the name for a chemical reaction that gives out heat to the surroundings?
Exothermic
Name 3 metals that are less reactive than hydrogen
Copper, silver, gold, platinum
True or False? Are halogens produced at the cathode?
False. Halogens are produced at the anode during electrolysis.
What type of bonding is used in metals?
Metallic bonding
Name one use of aluminium
Aircraft bodies, food cans or power cables
What is higher in a reaction profile diagram for an endothermic reaction, the products or the reactants?
Products
What happens at the cathode during the electrolysis of molten lead (II) bromide?
Lead is formed
What is electroplating?
Electroplating is a process where the surface of one metal is coated with a layer of a different metal
Why is aluminium oxide dissolved into molten cryolite?
This is because aluminium oxide has a melting point of over 2000 °C which would use a lot of energy and be very expensive
Why is zinc used for sacrificial protection?
Zinc is more reactive than iron, so it corrodes (oxidizes) first.
In an experiment, the temperature of a solution increases when two substances are mixed. What does this tell you about the type of reaction, and what is happening in terms of energy transfer?
Exothermic reaction, and energy is being transferred to the surroundings as heat
What happens at the anode during the electrolysis of aqueous sodium chlorine?
Chlorine gas is formed.
Name 2 advantages of a hydrogen fuel-cell
Hydrogen can be produced from water so the process is renewable
They do not produce any pollution: the only product is water whereas petrol engines produce carbon dioxide, and oxides of nitrogen
They release more energy per kilogram than either petrol or diesel
No power is lost in transmission as there are no moving parts, unlike an internal combustion engine
Quieter so less noise pollution compared to a petrol engine
Give the formula of slag and its state.
CaSiO3 (l)
Give the word equation for when a metal reacts with water
metal + water → metal oxide + hydrogen
During a chemical reaction, bonds are broken and new ones are formed. Breaking bonds requires this, while making bonds releases it. What is this?
Energy (input / output)
Create the half ionic equation for the electrolysis of Dilute sulfuric acid (H2SO4) at the anode
4OH– → O2 + 2H2O + 4e–
A student is setting up an experiment to electrolyse copper(II) sulfate solution.
The student can choose either carbon (graphite) or copper electrodes for the experiment.
Copper electrodes because copper electrodes take part in the reaction. The anode loses copper ions and the cathode gains copper, changing their mass.
Give the symbol equation for the reduction of iron (III) by carbon monoxide (include state symbols)
Fe2O3 (s) + 3CO (g) → 2Fe (I) + 3CO2 (g)
Give the 2 half equations for the extraction of aluminium from bauxite?
Al3+ + 3e- → Al
2O2- → O2 + 4e-
How much heat energy is required to heat up 10 grams of water with a 4.2 specific heat capacity by 5 degrees?
210 J