Electrolysis, Dynamic Equilibrium and Electroplating (paper1) Flashcards
Name a use for gold and why
Spacesuit visors for radiation protection
Name a use for copper and why
Building construction and wiring because it can conduct electricity
Name a use for aluminium and why
Overhead electrical cables because it resists corrosion, does not conduct electricity
What is brass
An alloy of copper and zinc
What happens to ions of a substance when dissolved in water
They are free to move
Define electrolysis
A process where electricity is used to make a chemical change happen that wouldn’t happen otherwise
Name all diatomic elements
Br, I, N, Cl, H, O, F, At
What does not spontaneous mean
Doesn’t happen on its own
What forces electrolysis to happen
electrical energy from a battery
What happens at the anode
Oxidation, and it pulls the electrons
What happens at the cathode
Reduction, and it pushes electrons
What happens to elements that don’t have a charge
They pair up
At the anode, what is the layout of the half equation
X->X+Y
At the cathode, what is the half equation layout
X + Y->X
What are the ions called that go to the anode
Anions
What are the ions called that go to the cathode
Cations
How many ions are present when electrolysing molten substances
2
What is the most common type of reversible reaction
Biochemical, they take place in living organisms
What is an important industrial reaction
The Haber process
What are the names for the ways the reaction moves
Endothermic and exothermic
When is the reaction exothermic
When it’s giving out heat
When is a reaction endothermic
When it gets colder or absorbs heat
What happens at a certain point in a reversible reaction
Both forward and backward reactions are happening at the same speed so the amount of products and reactants aren’t changing
Where does a dynamic equilibrium only occur
A closed system
What would happen if it was in an open system
Gases would escape and so equilibrium would not be achieved
What’s the haber process equation
Nitrogen+hydrogen<=> ammonia
What are the three factors we can change to influence the position of an equilibrium
Temp, concentration, pressure
Do an equilibrium have to be in the middle
No
What happens if the reaction increases in temp
It moves in the endothermic direction
What happens if the reaction decreases temp
It moves in the exothermic direction
What happens if we increase the gas pressure in a reaction
It moves in the direction that forms fewer gas molecules
What happens if we decrease the gas pressure
It moves in the direction that forms more gas molecules
What happens if we increase the concentration in a reaction
It moves in the direction that uses up the substance that has been added
What happens if we decrease the concentration in a reaction
It moves in the direction that forms more the substance that has been removed
What happens if you add a catalyst to the reaction
It stays the same
Where does the hater process get its nitrogen
The air
Where does the haber process get its hydrogen from
Natural gas
What conditions does the haber process have to have to work
High temps- Temp of 450^
High pressure- 20x normal atmospheric
The presence of an iron catalyst
What comprise is made in the haber process
A higher temp = a quicker rate of reaction but it produces less ammonia so 450 is a compromise
What does higher pressure in the haber process produce
More ammonia
What does the high pressure in the haber process run the risk of
Explosions
What is electroplating used for
Preventing corrosion or to make something pretty
What is electroplating
Coating the surface of one metal with a thin layer of another metal
What are the best electrical conductors
Silver and copper
What are the downsides of electroplating with silver and copper
They tarnish in air
Explain the advantages and disadvantages of gold electroplating
It’s a good conductor and doesn’t tarnish but it’s expensive
What is the object that is to be electroplated
The cathode
What can iron and steel be covered in to prevent rusting
Zinc
What is the process in which zinc covers iron
Galvanising
What is zinc acting as
A sacrificial metal that stops water reaching the iron or steel
Does sacrificial protection still happen if the layer of zinc is damaged?
Yes
What is an alloy
A mixture of a metal element with one or more other elements
How is an alloy steel made
By adding other elements to iron
How do you create different properties in alloy steels
Change their composition
What steel resists rusting
Stainless steel
What does stainless steel contain
Chromium, which reacts with oxygen to form chromium oxide
What are the ions called in a displacement reaction that don’t change
Spectator ions
What’s a redox reaction
A reaction where one substance is oxidised and one substance is reduced
What is the ionic equation for every BAWS reaction
OH- + H+ -> H2O
