Revision Flashcards
Relative atomic mass
Average mass of all the isotopes of an element compared to 1/12th the mass of an atom of Carbon-12
Steps of mass spectrometry
Electrospray ionisation, acceleration, ion drift, ion detector, data analysis
Describe electrospray ionisation
A sample is dissolved in a volatile solvent (water/methanol) and injected through a fine needle attached to high voltage power supply. The particle gains a proton, forming 1+ ion
Acceleration
The ion accelerated towards a negatively charged plate
Ion drift
Travel through flight tube with different velocities (because of different masses)
Ion detection
When the ion hit the plate, it gains an electron, producing a current, which is detected by the detector
Data analysis
Showing relative abundance and mass to charge ratio (m/z)
Why Cr has an unusual electron configuration?
Half-filled 3d subshells to be more stable
Why Fe has an unusual electron configuration?
Fully-filled 3d subshells to be more stable
Definition of isoelectronic
Particles with same electron configuration
Plum pudding model
- positive pudding (not empty spaced)
- negative electron
- no energy shell
Covert m^3 to dm^3 and cm^3
1 m^3 = 1000 dm^3 = 1000000 cm^3
Ideal gas equation with units
pV= nRT
(Pa)(m^3) = (mol) (JK^-1mol^-1)(K)
Percentage yield
(Actual yield/ theoretical yield) x 100
Atom economy
(Molecular mass of desired production/ total mass of reactants) x 100
Why is percentage yield not 100%?
- lost in transfer
- not all reactants have fully reacted
Why conical flask does not have to be fully dry?
Doesn’t affect the number of moles of the solute
Why using conical flask?
Easier to swirl
Prevent spitting out
Why placing a white tile?
To view the indicator colour more clearly