Quantitive Stuff (paper1) Flashcards
What is theoretical yield
Maximum mass of a product can be formed from a given amount of a reactant
What is percentage yield
The actual yield is the actual mass of product formed a reaction
What is the equation for percentage yield
=actual yield divided by theoretical yield x 100
What is the equation for moles
Moles = mass divided by RFM
What is atom economy
A method of showing how efficient a particular Reaction makes use Of the Atoms in the reactants
What does atom economy show
Mass of useful products by percentage
What’s the atom economy equation
RFM of useful product divided by the sum of RFMs of all reactants
Why is the atom economy usually not 100%
Either something reacted with something to make a waste product, or some gases escaped from the closed system, or some product is left behind on apparatus
What is Avogadro’s number/the value of 1 mole
6.02x10 to the power of 23
What is gas measured in
Dm cubed
What is 1dm cubed equivalent to
1 litre or 1000cm cubed
If gases are at the same temp and pressure, then what else will they have to same
Same amount of particles
What is molar gas volume
The volume occupied by one mole of molecules of any gas
What is the molar gas volume at rtp
24dm cubed
What does rtp mean
Room temp and pressure
What is the equation for volume of gas
Amount of gas(mol) x molar volume
What is the equation for amount of gas
Volume divided by molar volume
How do you change dm cubed to cm cubed
Multiply by 1000
How do you change cm cubed to dm cubed
Divide by 1000
What is the equation for concentration
Mass of solute in grams divided by volume of solution in dm cubed
What is another equation for concentration
Number of moles of solute divided by the volume of solution in dm cubed
What’s the definition of a fertiliser
A fertiliser provides mineral irons to facilitate plant growth and replace nutrients in soil that have already been absorbed by plants
What are important elements to plants
Nitrogen, phosphorus and potassium
What form must the fertiliser be in to be absorb
A soluble form(liquid)
What part of the plant absorbs the fertiliser
Root hair cells
What is a source of a soluble nitrogen compound
Nitrogenous fertilisers
What is ammonium nitrate
A salt manufactured by reacting ammonia solution with dilute nitric acid
How is nitric acid manufactured
It is manufactured from ammonia in stages
How is ammonium sulphate made
In a laboratory by reacting ammonia solution with dilute sulphuric acid
Explain the process of making ammonium sulphate in a lab
It is on a small scale and uses titration. It’s also made in batches
Explain the process of making ammonium sulphate in a factory
Large scale, several stages and it’s continuously made
Name the 4 factors affecting equilibrium
Temp
Pressure
Concentration
Catalyst
What can the 4 factors also affect
The rate of reaction
Where do factors affecting equilibrium only happen
In a closed system
What are some of the factors that chemical manufacturers have to take into consideration while making their product
It needs to be the appropriate amount of yield in an appropriate amount of time
They sometimes don’t allow the reaction to go to equilibrium if it will take ages and cost lots
What does a percentage yield calculation give no indication of
The amount of waste products
How can you improve the atom economy
Find uses for the by-products
Why should you measure the volume if something from the bottom of a meniscus
To avoid a error
What is concentration
The amount of solute dissolved in a stated volume of solution
What are acid-alkali titration used for
To find the exact volume of acid that neutralises a specific volume of alkali or vice-versa
What is a mole ratio
The ratio in moles of a the substances in a balanced equation
What could happen to plants if they are mineral-deprived
Have stunted-shoots or discoloured leaves
Where is ammonia solution and dilute sulphuric acid brought in from for laboratory making of ammonium sulphate
Chemical manufactures
Where is ammonia solution and dilute sulphuric acid brought in from for industrial production making of ammonium sulphate
It isn’t brought in, it’s made on site from their raw materials
Why is the industrial process of making ammonium sulphate stopped occasionally?
For maintenance and cleaning of the machinery
What factors effect the reaction pathway that is chosen
Availability and cost of raw materials and energy supplies
Rate of reaction and equilibrium position
Atom economy, yield and usefulness of by-products
In the past, what way was nitric acid made
Using the Birkland-Eyde process
What was wrong with the Birkland-Eyde process
It’s yield of nitrogen monoxide was only 4% and it used huge amounts of energy
What method is now used for making nitric acid
The Ostwald process
What do chemical cells have
Two different metals, each dipped into a solution of one of their salts and a salt bridge to allowed dissolved ions to pass from one solution to another
Where do chemical cells store their reactants
Inside
Where do fuel cells store their reactants
They don’t, they get them from the outside
Do fuel cells go flat
No as they produce a voltage for as long as reactants are supplied
Why are hydrogen-oxygen fuel cells and electric motors better than petrol and Diesel engines
They are quieter and need less maintenance
