Unit 3 - Quantitive Chemistry Flashcards
What is avagadros number
6.02x 10 to power of 23
What is a mole
Amount of a substance
Equation relating volume, mass and Mr
Volume = (mass / Mr) x 24
At room temp (20)
Equation for concentration
Concentration = mass in g / volume in dm3
How to covert g into dm3
Divide by 1000
Atom economy equation
Mr of desired products / Mr of all reactants x 100
Equation for percentage yield
(Mass of product actually made / theoretical mass produced) x 100
Why will the percentage yield not be 100%
Lose materials when transferred from one container to another , some will always get left behind
How do you get from g/dm3 into mol/dm3
Divide by the Mr
Explain difference between pipette and burette
Pipette measure fixed volume
Burette measures variable volume (drop by drop)
How do you get from the number of particles to the number of moles
Times by avagadros number
Ways to work our moles using energy
Energy required / energy for one mole = moles
Why is percentage yield not 100%
Practical losses during experiment such as during pour or filtering
Side reactions occurred
Incomplete reactions in which some reactants do not react to form the product
Name 3 strong acids
Hydrochloric, nitric, sulphuric,
Name 3 weak acids
Carbonic acid, citric acid and ethanoic acid
What is ph of a solution the measure of
Concentration of H + ions
Explain why an acid can be described as both strong and dilute
Strong because completely ionised in aqueous solution and dilute because small amount of acid per unit volume
What conditions has to occur for one moles of any has a volume of 24 dm3
Room temp and pressure
What does inert mean
Unreactive
Why should electrodes be inert
to avoid any unwanted chemical reactions with the electrodes themselves
What happens at the cathode (talk about electrons)
Gain electrons
What happens at the anode (electrons)
Lose electrons
What is the limiting reactant
the reactant that is all used up in the reaction
What does it mean when a reactant is in excess
reactants that are not used up when the reaction is finished are called excess reagents
Equation to work out volume using just moles
Volume = moles x 24
Colour change of phenolphthalein
Colourless in acid to pink in alkali
Why use a white tile in the titration RPA
So you can see the colour change easier
What type of reaction is a titration
Neutralisation
