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Physical Chemistry (PI5.2 Acid-base equilibria)

6 dot points across 6 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

How do we calculate the pH of strong and weak acids, and how do buffers resist changes in pH?

The pH scale, Ka and pKa for weak acids, the ionic product of water Kw, calculating the pH of strong and weak acids and bases, buffer solutions and titration curves with indicators.
An Eduqas A-Level Chemistry PI5.2 answer on the pH scale, Ka and pKa, the ionic product of water, calculating pH for strong and weak acids and bases, buffers and titration curves.
13 min answer →

How do rate equations, orders of reaction and the rate-determining step reveal a reaction mechanism?

Rate equations and orders of reaction, the rate constant, determining orders from concentration-time and rate-concentration data, the rate-determining step, and the Arrhenius relationship with activation energy.
An Eduqas A-Level Chemistry PI3 answer on rate equations and orders of reaction, the rate constant, determining orders from data, the rate-determining step and the Arrhenius equation.
12 min answer →

How do Born-Haber cycles and enthalpies of solution let us quantify the energetics of ionic compounds?

Lattice enthalpy, Born-Haber cycles, the enthalpy changes of formation, atomisation, ionisation, electron affinity and lattice formation, and enthalpies of solution and hydration.
An Eduqas A-Level Chemistry PI4.1 answer on lattice enthalpy, Born-Haber cycles, the component enthalpy changes, and enthalpies of solution and hydration.
12 min answer →

Why do some endothermic reactions happen spontaneously, and how does entropy decide feasibility?

Entropy and its changes, the total entropy change, Gibbs free energy, the condition for feasibility, and the effect of temperature on the feasibility of a reaction.
An Eduqas A-Level Chemistry PI4.2 answer on entropy and entropy changes, Gibbs free energy, the condition for feasibility, and how temperature affects whether a reaction occurs.
12 min answer →

How do we quantify the position of an equilibrium with Kc and Kp, and what changes their value?

The equilibrium constants Kc and Kp, writing their expressions, calculating their values and units, and the effect of temperature, concentration, pressure and catalysts on the constant and the position of equilibrium.
An Eduqas A-Level Chemistry PI5.1 answer on the equilibrium constants Kc and Kp, writing and calculating their expressions and units, and the effect of changing conditions on K and on the position of equilibrium.
12 min answer →

How do we measure the tendency of a species to be reduced, and predict whether a redox reaction will occur?

Oxidation states and half-equations, the standard hydrogen electrode, standard electrode potentials, electrochemical cells and their EMF, and using electrode potentials to predict feasibility.
An Eduqas A-Level Chemistry PI1.1 answer on oxidation states and half-equations, the standard hydrogen electrode, standard electrode potentials, cell EMF and predicting feasibility.
12 min answer →