Paper 3 PAG Markscheme Flashcards
How to reduce uncertainty with the same equipment ( change of mass temp)
MEASURE MASS DIRECTLY
- by tearing the mass of bottle to 0 so that only one mass change
- hence only once uncertiwnties is used
How else to reduce uncertainty for same apparatus in terms of changing amount
Increase the amount, likely to increase the finsk tempertaure or mass, which leads to a lower percentage uncertiwnity
Safety alerts and precautions for heating lead with methane
Compounds could be toxic, hence use fume cupboard
Any methane etc highly flammable hence keep away from flame
Compounds poisonous hence wear GLOVES
How to ensure all oxygen reacted
1) heat till constant mass
2) bubble through limewater and when white precisptpe no longer made it’s done
3) REACT WITH EXCESS GAS SO THAT ALL REACTS
4) dint react with air instead pass with cool or inert gas to avoid other reactions
Remember how to Identify phenol
PH test and less than 7
No reaction with sodium carbonate
What is ligand sub
One ligand replaces another
2 ways to see how metal reaction done
No more effervescence
Metal solid has dis seal red / dissolved
How to make standard so,Union
Dissolve in beaker less than 250
- transfer into volumetric flask and washings
- make up to graduation mark with water
- invert several times to ensure even mixing
And use dropping piepere to hit graduation
Why can we assume order to be zero?
Large excess , much higher concentration
How to change experiment so that can prove something else is this order
Just keep the other CONSTSNT
Monitor the conc of this with time
- and see how it affects the rate
OR
-use initsl rate, measure the rates initially with change of conc, and see if it causes Frist order etc
PV = NRT convert units must be m3!
So if cm3 then 10^-6
IF dm^3 then 10^-3
NKT 10^3 !! And check the stoichemetry read entire q
Can do molar ratios between I dicusk xlecies too
This can give you some idea how to balance
