Simulation · Chemistry · Class 11
Heating limestone in a closed vessel
From the lesson Homogeneous and heterogeneous equilibria; Kp in Equilibrium. Change the values and watch what happens.
Heating limestone in a closed vesselChemistry · Class 11
The idea behind it
NCERT § "Homogeneous Equilibria"; § "Heterogeneous Equilibria"
- In a homogeneous equilibrium all species are in the same phase, such as all gases or all in one solution.
- For gases, partial pressures can replace concentrations, giving Kp; the two are linked by Kp = Kc(RT)^Δn.
- Δn = (moles of gaseous products) − (moles of gaseous reactants) from the balanced equation.
- When pressure is in bar and concentration in mol L⁻¹, R = 0.0831 bar L mol⁻¹ K⁻¹.
- If Δn = 0 (e.g. H₂ + I₂ ⇌ 2HI), Kp = Kc; for PCl₅(g) ⇌ PCl₃(g) + Cl₂(g), Δn = +1 and Kp = Kc(RT).
- In a heterogeneous equilibrium more than one phase is present, such as water in equilibrium with its vapour or CaCO₃(s) ⇌ CaO(s) + CO₂(g).
- The concentrations of pure solids and pure liquids are constant and are left out of the K expression; for the decomposition of CaCO₃, Kp = p(CO₂).
- Even though pure solids and liquids do not appear in K, they must be present for the heterogeneous equilibrium to exist.