All competitions
International Chemistry Olympiad (IChO)
The International Chemistry Olympiad (IChO) is held every summer. Each country sends a team of up to four school students, who sit two five-hour exams, one theoretical and one practical.
The host nation must publish preparatory problems in advance, which set out the advanced topics that may come up beyond the common syllabus.
How to prepare here
- Plan your attack in Approach mode, and derive rate laws in Mechanisms; any of the library formulas could come up.
- Reviewing what Progress marks as due each day.
- At university level, K is unitless: see the Book page on Kc, Kp and activities for why. Functionally, just use bar for Kp and M for Kc.
Conventions
- As the question requires.
- Units: SI; CODATA constants.
IChO question types (49)
- ΔG from ΔH and ΔS
- K from ΔG°
- ΔG° from K
- K from ΔH° and ΔS°
- van 't Hoff: K at a new temperature
- First order: concentration after time t
- Activation energy from two rate constants
- Second-order half-life
- Steady state: A ⇌ I → P
- Pre-equilibrium then half-life
- Lindemann–Hinshelwood fall-off
- Michaelis–Menten rate
- Radioactive decay: elapsed time
- ΔG‡ from a rate constant
- pH of a weak acid
- Buffer pH (Henderson–Hasselbalch)
- Moles of an ideal gas
- ΔG° from E°
- Nernst equation
- ΔH at another temperature (Kirchhoff)
- Boiling point at reduced pressure
- Entropy change on heating
- Hess's law from enthalpies of formation
- ΔH from a bomb-calorimeter ΔU
- Kp from Kc
- Solubility from Ksp
- pH of a weak base
- Mass deposited by electrolysis
- E°cell from reduction potentials
- Concentration from absorbance
- Wavelength to break a bond
- Density of a rock-salt crystal
- Atomic radius of a face-centred cubic metal
- Atomic radius of a body-centred cubic metal
- Unpaired electrons from a magnetic moment
- Crystal field splitting from a d–d absorption
- Latimer diagram: skipping an oxidation state
- Disproportionation constant from a Latimer diagram
- Water hardness by EDTA titration
- Nickel by EDTA back titration
- Apparent activation energy of a pre-equilibrium mechanism
- 2NO + O₂: pre-equilibrium with bimolecular steps
- Lindemann mechanism at a given pressure
- Methanol synthesis: K from tabulated data
- Daniell cell away from standard conditions
- pH of benzoic acid from a weighed sample
- From ΔG‡ to a reaction time at another temperature
- Enzyme kinetics from elementary rate constants
- H₂ + I₂ ⇌ 2HI: equilibrium amounts
Book pages for this level
- Two-point Arrhenius and van ’t Hoff
- Steady state vs pre-equilibrium
- Deriving rate laws: Lindemann and Michaelis–Menten
- Kc, Kp and the unitless K
- Combining electrode potentials
- Octahedral crystal field splitting
- Choosing a hydride reducing agent
- The Diels–Alder reaction
- Buffers and the Henderson–Hasselbalch equation
Plus 72 reagents to drill in the reagent trainer.