Equilibrium · expressions and response
Understand Kc
Practise Kc expressions, then use the Haber model to test changes in concentration, pressure, temperature and catalyst. For full Kc and Kp calculations, use the linked equilibrium sets.
Dynamic equilibrium model
N₂(g) + 3H₂(g) ⇌ 2NH₃(g)
Exothermic forward reaction, ΔH ≈ −92 kJ mol⁻¹. This teaching model uses illustrative Kc values while keeping every shift and equilibrium calculation consistent.
Equilibrium concentrations
System data
- Volume
- 10.0 dm³
- Temperature
- 400 K
- Kc at this temperature
- 0.500
- Current Qc
- 0.500
Ready for the calculation chain?
Move from equilibrium moles to concentration or partial pressure, then calculate Kc or Kp with diagnostic feedback on characteristic wrong results.
Kc and Qc
Kc is fixed for a given reaction at a given temperature. Qc uses the concentrations at the current moment. After a disturbance, the system shifts until Qc equals Kc again. Only a temperature change alters Kc.