Category:Physical

Physical chemistry looks at the basics of chemical reactions and interactions.

Redox Reactions

Oxidation is the loss of electrons and reduction the gain, redox reactions involve a change in the oxidation states of compounds. Redox reactions show this change and can be made by combining half equations. See Redox Reactions

Redox Equilibria

Essential to redox reactions is the variable oxidation states of transition metals. Electrode potentials can be set up, these show how strong a reducing agent the metal is. The hydrogen electrode is the standard. See Redox Equations

Rates of Reaction

Collision theory is essential to rates of reactions. The Maxwell-Boltzman Distribution shows how much energy molecules have and whether it is enough for a reaction. Factors affecting rate are concentration, surface area. See Rates of Reaction

Kinetics

The rate of a reaction can be expressed in the rate equation using the orders of a reaction. The order of reaction is determined by performing expreiments with various concentrations. The units of k vary. See Kinetics

Hess's Law

Hess stated that the energy change in a reaction is the same regardless of the route, therefore we can create alternative routes and use the enthalpies to calculate the overall enthalpy change for a reaction. See Hess's Law

Further Enthalpy

Definitions of various enthalpies (electron affinity, hydration, atomisation, solution etc.). Using the Borne-Haber cycle. And the mean bond enthalpy as an estimation of the average enthalpy change. See Further Enthalpy

Enthalpy Change

What is enthalpy and the notation used. Definitions of the enthalpy of combusion reaction and formation. The use of calorimetry as a way of estimating the enthalpy change of a reaction. See Enthalpy Change

Gibbs Free Energy and Entropy

The feasibility of a reaction depends upon the enthalpy change and the entropy change (change in the degree of disorder in a system). How to calculate entropy change and how it changes with temperature. See Entropy and Free energy

Equilibrium Constants

An equilibrium constant tells you how far to the left of right a reaction is. There are two constants: Kc using concentrations for solution and Kp using partial pressures for gases. How changing conditions affect the value. See Equilibrium Constants

Equilibria

Reversible reactions form an equilibria. The position of this equilibria depends upon the various conditions with Le Chatelier's Principle stating the equilibria will oppose any change. This is applied in industry to maximise reactions. See Equilibria

Brønsted-Lowry Acids and Bases

Acid and bases are defined in terms of protons in this definitions; giving rise the the value of pH. The ionic product of water is Kw can be used in calculations and Ka for weak dissociation. See Brønsted-Lowry Acids and Bases