Studied by 21 people
What is concentration?
A measure of how much of a substance is present in a given volume
Units of concentration?
g/dm³ or mol/dm³
How can concentration be calculated?
Concentration (g/dm³) = Mass / volume Concentration (mol/dm³) = Moles / volume
How can you increase the concentration of HCl?
Decrease the volume of the solution Increase the number of moles of HCl
Cm to dm
divide by 1000
What is the molar volume of a gas?
the volume occupied by one mole of a gas at room temperature and pressure
What is RTP?
Room temperature and pressure:
20oC
1 atmosphere
What is the molar volume of gas at RTP?
24 dm^3
What is yield?
The amount of product you get from a reaction
Why do you never get 100% yield?
some reactants may be left behind in the equipment
there may be side reactions where a substance reacts with a gas in the air
the reaction may be reversible and the products are continually turning back into the reactants
What is the theoretical yield?
the amount of product that would be obtained under perfect conditions
What is the percentage yield?
a good way of measuring how successful a chemical process is a high percentage yield to increase profits and reduce costs/waste
Percentage yield equation
actual/theoretical x100
Atom economy
(Molecular mass of desired products/ Molecular mass of all products) x 100
What is an atom economy used for?
to analyse the efficiency of reactions
The higher the atom economy...
the more sustainable
What does atom economy study?
The amount of reactants that get turned into useful products
What reactions are unwanted
Those with low atom economies - unsustainable
What is desirable?
High percentage yields and fast reaction rates
Equipment needed for titrations
burette
pipette and pipette filler
conical flask -white tile
funnel
clamp and stand
What are concordant results?
Results within 0.1 cm³ of each other
What are titrations?
A method of analysing the concentrations of solutions. Used to determine exactly how much alkali is needed to neutralise a quantity of acid
What are indicators in titrations used for?
To show the endpoint in a titration
Why is universal indicator not suitable in a titration?
It gives a range of colours and not a sharp endpoint
Why is litmus not suitable in a titration?
the colours are similar
Note 
Flashcard (85)