Topic 5- Quantitate analysis Flashcards
How to find mass using conc + volume?
Mass (g) = (conc g/dm^-3)(volume dm^-3
How to find moles using conc + volume?
Moles = (Conc mol/dm^-3) x (Volume dm^-3)
How to convert cm^3 into dm^-3?
/1000
How to convert mol/dm^-3 into g/dm^-3
(mol/dm^-3) x (Mr or relative formula mass)
Core Practical: Carry out an accurate acid-alkali titration, using burette, pipette and a suitable indicator
1) add acid to buiret using a funnel
2) Record volume of acid
3) Add known volume of alkali to conical flask
4) Place flask on white tile to see clear colour change
5) Add indicator e.g phenolphthalein (pink in alkali, colourless in neutral or acid)
6)Add acid relatvely slowly until colour change
7) Record volume of acid used
8) Repeat experiment, drop by drop around the volume of acid needed —> precise
Percentage yeild=
Amount of product/maximum amount of possible product
Why is the percetnage yield smaller than the theoretical percentage yield?
-Incomplete reactions (not all reactants react)
-Practical losses e.g some reactant left in wieghing boat
-Side reactions (some reactants react to form different products accidently)
What is the atom economy?
Mr of desired product/ Mr of all reactants
What is atom economy used for?
-Industry
-See how economically wasteful certain reactions are
What is is the best pathway for a reaction?
-Highest atom economy
-High yield
-Fast reaction
-Equilibrium to the right (towards products)
-Useful byproducts
What is the molar volume of 1 mol of gas?
under room temp + pressure (20 and 1)
-2400 cm^3
-(22.4 litres/mole)
Equation for volume of gas at RTP?
Volume dm^-3 = moles x 24dm^-3
What is avagrado’s law?
no. of particles = moles x Ar
