Things you need to Memorise Flashcards
Weak Acids
Citric Acid Hydrofluoric acid Ethanoic acid Phosphoric Acid Carbonic Acid
Soluble: Nag SAG
Nitrate
Acetates
Group 1
Sulfates
Ammonium
Group 17
Solubility Exceptions PMS CASTRO BEAR:
PMS with SULFATES & GROUP 17
P (Pb, Lead)
M (Hg, Mercury)
S (Silver, Ag)
CASTRO BEAR with SULFATES
Ca (Calcium)
Sr (Strontium)
Ba (Barium)
Acidic and Basic salts
ACIDIC always NH4 (ammonium)
Strong Base + Strong Acid = Neutral
Strong Base + Weak Acid = Basic
Weak Base + Strong Acid = Acidic
Strong Bases
Weak base
NaOH
KOH
Ca(OH)2 –> Calcium hydroxide
Any other hydroxide with Group 1 & 2 Metals
Ammonia and everything else
Indicator and pH range for titration reactions
Indicator pH range of colour change
Methyl orange Strong Acid + Weak Base (Low pH)
Phenolphthalein Strong Base + Weak Acid (High pH)
Bromothymol blue Strong Acid + Strong Base (Neutral)
4 reasons that show a chemical system has reached equilibrium:
- It is a closed system - no matter enters or leaves the system
- Macroscopic properties (e.g. state, colour, temperature and pressure) stay constant
- Concentrations of reactant and products stay constant
- Rate of forward reaction = rate of reverse reaction
What is the enthalpy, entropy, and Gibbs free energy for Photosynthesis?
Enthalpy ∆H
- Positive
- Endothermic reaction
Entropy ∆S
- Negative
- Decrease in particles
Gibbs Free Energy ∆G
- Positive
- Non-spontaneous
What is the enthalpy for combustion?
Negative because it is an exothermic reaction
2, Effect of concentration on equilibrium
If concentration of a reactant or product is increased, the equilibrium will shift to the other side to use up the added chemical.
If concentration of a reactant or product is decreased, the equilibrium shifts to replace the substance removed.
2, Effect of Pressure and Volume Changes on Equilibrium
If pressure is increased, volume decreases. This will be towards the side with fewer gaseous particles. Because there are fewer collisions.
If pressure is decreased, volume increases. This will be towards the side with more gaseous particles. Because there are more collisions.
2, Effect of Temperature Changes on Equilibrium
If temperature of an equilibrium system increases the equilibrium position moves in whichever direction absorbs heat
If temperature of an equilibrium system is decreased, the system will move in whichever direction produces more heat.
2, Effect of a Catalyst on Equilibrium
Adding a catalyst will provide an alternative pathway of lower activation energy - this will allow both the forward and reverse reactions to occur at a faster rate
No visible effect
Changes in Temperature - Equilibrium Graph
It is going to gradually affect both reactants and products
Changes in Concentration - Equilibrium Graph
After the equilibrium is disturbed the change will show a sharp spike - ONLY one spike