Edexcel A Level Chemistry:復習筆記5.4.3 Gibbs Free Energy
Feasibility of Reactions Gibbs free energy The feasibility of a reaction is determined by two factors The?enthalpy?and?entropy change The two factors come together in a fundamental thermodyn...
Edexcel A Level Chemistry:復習筆記5.4.2 Entropy Calculations
Total Entropy Calculations If we take the reaction between sodium and chorine, we know that this is a very exothermic reaction and also involves a decrease in entropy as a solid is produced ...
Edexcel A Level Chemistry:復習筆記5.4.1 Introducing Entropy
Introducing Entropy You may have wondered why it is that?endothermic?reactions occur at all, after all, what can be the driving force behind endothermic reactions if the products end up in a...
Edexcel A Level Chemistry:復習筆記5.3.4 Enthalpy of Solution
Solution & Hydration Definitions Enthalpy of solution The?standard enthalpy change of solution (ΔHsol?)?is the enthalpy change when?1 mole?of an ionic substance?dissolves?in sufficient w...
Edexcel A Level Chemistry:復習筆記5.3.3 Polarising Power
Polarisation of Ions Theoretical lattice energies assume a perfect ionic model where the ions are 100% spherical and the attractions are purely electrostatic So overall, there has a been a c...
Edexcel A Level Chemistry:復習筆記5.3.2 Born-Haber Cycles
Born-Haber Cycles A?Born-Haber cycle?is a specific application of Hess’ Law for ionic compounds and enable us to calculate lattice enthalpy which cannot be found by experiment The basic prin...
Edexcel A Level Chemistry:復習筆記5.3.1 Lattice Energy
Lattice Energy Lattice energy As with bond enthalpy,?lattice energy?(ΔHlatt?) can be expressed as a formation or dissociation process As a formation process, it is the enthalpy change when?1...
Edexcel A Level Chemistry:復習筆記5.2.8 Weak Acid - Strong Base Titration
Weak Acid - Strong Base Titration In this example, strong sodium hydroxide, NaOH (aq), is being added to weak ethanoic acid, CH3COOH (aq) NaOH (aq) + CH3COOH (aq) →?CH3COONa (aq) + H2O (l) T...
Edexcel A Level Chemistry:復習筆記5.2.7 Buffers
Action of a Buffer Solution A?buffer solution?is a solution which resists changes in pH when small amounts of acids or alkalis are added A buffer solution is used to keep the pH almost const...
