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Topic 5c - Dynamic equilibrium - Coggle Diagram
Topic 5c - Dynamic equilibrium
Reversible reactions
A reaction where the products of the reaction can react to produce the original reactants
They have a double arrow, showing the reaction can go in either direction
Faster equilibrium
Higher temperature used - more kinetic energy so more frequent collisions that are successful
Higher ptessure means more particle is a given volume, so more frequent successful collisions
A catalyst is used
Dynamic equbilibrium
If a reversible reaction takes place in a closed system, then a stat of dynamic equilbirium will be reached
Dynamic equilibrium is when the amount of reactants and products reach a balance - their concentrations remian constant, and the forward rate equals the backward
A closed system means that none of the reactants or products can escape and nothing else can get in
Origionally, in a reversibe reaction, the reactants react and their conentrations fall, so the forwards reaction slows
As more products are made, their concentrations rises and the backward reaction speeds up
After a while, the forward and backward will be going at the same rate, the system reaches dynamic equilibrium
Both reactions still happen, but the overall effect is nil as the forward and backward reactions cancel out
Equal
A reaction at equilibruim doesn't meant the amount fo reactants equal the amount of products
If equilibrium lies to the right, concentration of products is greater
If equilibrium lies to the left, concentration of reactants is greater
Fertilisers
Elements
Three main elements needed by plants are nitrogen, phosphorous and potassium
Plants absorb these nutrients from the soil
Fertilisers replace these elements if they're missing, increases crop yield
Ammonia based fertilisers
Contain compounds derived from the haber process
You can control the compositions of chemicals in them
Solube so the chemicals can dissolve down into the soil
Nitrogen compountds
Ammonia can react to form other compounds
Reactign ammonia with oxygen and then water produces nitric acid, and can be reacted with ammonia to form ammonium salts
Ammonium nitrate has a high proportion of nitrogen per unit mass
ammonia + nitric acid -> ammonium nitrate
Ammonium sulpahte
Laboratory
Reacting ammonia with dilute sulfuric acid
Method
Set up a titration, and add a few drop sof methyl orange inidicator to ammonia solution
Add dilute sulfuric cid from burette into the ammonia solutionn until yellow colour changes to red, meaning the ammonia has been neutralised
The ammonium sulphate isn't pure, its got methyll orange, record the volume of sulfirc acid used and repeat without the indicator
To get solid ammonium sulfate crystals, gently evapourate the solution until only a little bit remains
Batch process
Small scale
Industry
Uses larger reaction chambers filled with ammonia gas
Sulfuric acid is sprayed into the chamber, where it reactants to produce ammonium sulfate powder
Large scale
Continuous process
Use raw materials to make ammonia and sulfuric acid
Fuel Cells
Chemical cells
Electrochemical cells that produce a volatage across the cell until one of the reactants has been used up
A fuel cell is a chemical cell that's supplied with a fuel and oxygen and uses the reaction between them to efficiently release energy
Uses two different electrolytes and a piece of filter paper acting as a bridge betwen the two electrolytes
Advantages
Suitbale for portable appliances
Cheap to manafacture
Disadvantages
May contain harmful substances
Dont produce a voltage when one is used up
Hydrogen-Oxygen fuel cells
Reaction between hydrogen and oxygen releases energy, which is used to produce a voltage
Can power electrical devices that the fuel is connected to
Advantages
Hydrogen fuel cells are much more efficient than fossil fuels
Fuel cells don't produce any harmful pollutants - no greenhouse gases or toxic gases
Only by products are water and heat
Could replace batteries, which are incredibly polluting to dispose
Disadvantages
Hydrogen takes up alot of space to store, and is very explosive
Hydrogen fuel is often made in ways which burn fossil fuels
Would be expensive to install widely