Notes From Past Papers Flashcards
What is the temperature at which the entropy of a perfect crystal is zero
0k
What is le chateliers principle
If a system is subjected to any change the system will readjust itself to counteract the applied change
Why use a pH meter instead of an indicator
If the colour change is too hard to see
Why use reflux
Prevent evaporation of volatile molecules
If titre values are small (<10) what can you do?
- tire ate a larger sample
* dilute the standard
Why use volumetric instead of gravemetric
If gravemetric would produce too little or no precipitate
Why would the optical activity of a solution decrease
When a racemic mixture has been formed
What is a covalent bond
One atom in the molecule provides both of the bond in electrons
Why doesn’t a primary haloalkane do Sn1
The carbonation is not stable enough to exists
What is an agonist
Mimics the natural response of the body
What is an antagonist
Prevents the natural response of the body
What is the pharmacophore
Area responsible for the desired effect
What is a receptor
Site where reaction occurs
Why do tertiary/secondary haloalkanes undergo Sn1
Have more than 1 alkyl group, which stabilises the molecules allowing the carbocation to be able to exist
Neon produced a red light because?
When electron falls down from promoted energy level, it emotes radiation from the red end of the spectrum
Describe the emission spectrum
- energy absorbed results in electrons being promoted to higher energy levels
- when it falls back down, energy is emitted in the form of a photon whose wavelength corresponds to (colour) light
How is colorimeter my performed
- the absorbable of several solution of accurately known concentrations are measured
- a calibration graph is plotted with data
- absorbable of unknown is measured and compared against graph to deduce concentration
Why is NaOH an unsuitable standard
Low GFM
unstable is air (CO2)
absorbs moisture in air
In solvent extraction:
Why Gould you replace the aqueous layer with a different solvent instead of water
Less solute dissolves in that solvent
Why doesn’t benzene conduct electricity
The delocalised electrons are restricted to the ring
What is TMS
The standard referencing substance
What is a back titration
When the substance isn’t got rated itself but reacted with an excess solution
•then the remaining solution is reacted with something else to see how much was left over
What is homolytic fission and where does it occur
When the bond breaks and each atom in the bond receives an electron each forming free radicals
Usually occurs in non-polar covalent bonds
What is heterolyic bond fission and where does it occur
When one atom in the bond receives both the bonding electrons. This forms ions
Occurs between polar covalent bonds
