Hydrochloric Acid formula
HCl
Sulphuric acid formula
H2SO4
Nitric acid formula
HNO3
Ethanoic acid formula
CH3COOH
Sodium hydroxide formula
NaOH
Potassium hydroxide formula
KOH
Ammonia formula
NH3
What is the structure of ionic structures?
A lattice of repeated cations and anions, held together by electrostatic forces of attraction.
What happens when you dissolve ionic substances in water?
-Ions surrounded by water molecules, becoming hydrated/solvated
-[delta-] O atoms attracted to cations
-[delta+] H atoms attracted to anions
-Ions are thus separated, behaving independently
Define acid
A substance that releases H^+ ions in aqueous solution; an H^+/proton donors
Define alkali
A substance releasing OH^- ions in aqueous solution
Define base
A substance that neutralises acid to produce salt; a H^+/proton acceptor
What is a strong acid?
An acid which fully disassociates in water (e.g. HCl -> H^+ + Cl-)
What is a weak acid?
An acid which only partially disassociates in water (e.g CH3COOH -> CH3COO- only loses one H+, and is reversible)
What is neutralisation?
The reaction of acids with bases (oxides, carbonates, alkalis) to form salt; the reaction of H^+ and OH- to form H2O
How do you prepare a standard solution?
- Calculate amount of solid needed and weigh
- Dissolve in small amount of solvent in beaker
- Transfer to volumetric flask using a funnel
- Rinse beaker and rod into flask
- Fill flask to just below graduation mark, then bring level up using a teat pipette
- Stopper and invert flask to ensure thorough mixing
How do you carry out a titration?
- Fill burette up to 0
- Take rough initial titration (add acid/alkali until colour change)
- Take precise readings, adding until slight colour change, then dropwise until there is a permanent colour change
-Continue until concordant results are generated (within 0.1 cm^3)
What do you need to consider when carrying out titrations?
- Always use a funnel to fill a burette, but remove afterwards
- Read burette from bottom of meniscus, quoting to 2d.p
- No need to rinse after each titration
- (Exam) - always show construction lines
Define oxidation
OiL: Loss of electrons (increase in oxidation no.)
Define reduction
RiG: Gain of electrons (decrease in oxidation no.)
Where do roman numerals determining oxidation state go?
After ion/element with oxidation no./variable charge
e.g. FeO = iron (II) oxide
HNO2 = nitric (III) acid
K2CrO4 = potassium chromate (VI)
