12.9—The feasibility of a reaction depends on: i the balance between ∆Ssystem and ∆Ssurroundings, so that even endothermic

Understand that the feasibility of a reaction depends on: i the balance between ∆Ssystem and ∆Ssurroundings, so that even endothermic reactions can occur spontaneously at room temperature ii temperature, as higher temperatures decrease the magnitude of ∆Ssurroundings so its contribution to ∆Stotal is less Students should be able to calculate the temperature at which a reaction is feasible. Students may also use ∆G = ∆H - T∆Ssystem in answers, although this approach is not a requirement of the specification.

Use —the feasibility of a reaction depends on: i the balance between ∆ssystem and ∆ssurroundings, so that even endothermic to connect the rule to the data and decision in the question.

This matters because —the feasibility of a reaction depends on: i the balance between ∆ssystem and ∆ssurroundings, so that even endothermic determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply —the feasibility of a reaction depends on: i the balance between ∆ssystem and ∆ssurroundings, so that even endothermic to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: —The feasibility of a reaction depends on: i the balance between ∆Ssystem and ∆Ssurroundings, so that even endothermic is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.