A2 Chemistry 9701 Crash Course: Chemical Energetics

A series of flashcards covering key concepts in chemical energetics for the A2 Chemistry syllabus.

What is the definition of enthalpy change (ΔH)?

The amount of energy exchanged when a system undergoes a process under standard conditions.

What is meant by the term 'lattice energy'?

The amount of energy released when 1 mole of an ionic compound is formed from its gaseous ions under standard conditions.

How does lattice energy change with the charge and radius of ions?

Greater charge on an ion or smaller ionic radius results in stronger ionic bonds and more exothermic lattice energy.

What does a positive first electron affinity indicate?

Energy is absorbed to overcome the repulsion between two negatively charged species.

How does first electron affinity trend in Group 16 and Group 17 as you move down the groups?

It gets less exothermic down the group.

What is the Born-Haber cycle?

A thermochemical cycle used to calculate lattice energy based on Hess's law.

What can be said about the solubility of ionic compounds?

If the enthalpy change of solution is positive, dissolving is endothermic, which is unfavorable.

What trend is observed for the thermal stability of Group 2 carbonates as you move down the group?

Thermal stability increases down the group.

What does a negative Gibbs Free Energy change (ΔG) indicate about a reaction?

The reaction is feasible or spontaneous.

How does entropy change in a system as temperature increases?

Entropy increases as the kinetic energy of the particles increases, leading to greater disorder.