DON'T FORGET Flashcards
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EDTA USES
- detergents
- reduce hardness in water
- food stabliser
- medicine > prevent blood clotting
Explain why pH does not change in a buffer if volume slightly decreases/increases
- ratio of [HA] and [A-] stay constant
- concentration will change by the same amount.
RATES REMEMBER
A= pre-exponential term–> frequency of collisions with correct orientation.
- Gives rate of reaction if there is no activation energy
- A, K increases with temp
e^ (-Ea/RT) = no. of particles with energy to react
-gradient x R = Ea
strong alkali
completely dissociates releasing OH- ions
Redox titrations colour changes:
Manganate
MnO4 - –> Mn 2+
purple–> colourless/pale pink
Iodine-thiosulfate
S2O3 -2 –> S4O6 2-
brown –> pale yellow, then add starch –> dark blue –> colour has faded
Disproportion
same element in a reaction is oxidised and reduced
How to make a Mass against time graph
- Use of a flask where reaction occurs
- balence to weight mass
- Use of a stopwatch
- Record mass at time intervals (every 10-20 seconds)
d/s/p- block element
d- block element’s highest energy electron is in a d-sub shell.
How indicators change colour
- Acid (H+) added reacts with A-, and the equillibrium shifts towards HA.
- Alkali (OH-) added reacts with H+, and the equillibrium shifts towards A-.
- End point where equal amounts of HA and A- (intermediate of colours)
Choosing an indicator
Vertical section of titration curve matches the pH range of the indicator (where it changes colour).
The mole
the number of particles in 12g of Carbon-12.
enthalpy of Solution
-(lattice enthalpy) + (hydration entlapy)
Dative covalent bond
- shared pair of electrons have been supplied by one of the bonding atoms ONLY
Rate units
(moldm^-3) ^1-n
n= order
