The energy change of reactions (HT only) (5.5.1.3) | AQA GCSE Combined Science: Trilogy (8464) — Chemistry — Higher | KnowledgeSet

The energy change of reactions (HT only)

Chemistry (Combined Science) · GCSE · AQA · AQA GCSE Combined Science: Trilogy (8464) — Chemistry — Higher · Specification point · 5.5.1.3 · Energy changes · Exothermic and endothermic reactions

Calculating reaction energy change from bond energies

Energy transfer in bond breaking and bond making

Next Steps

Read Notes

Read clear notes for this topic.

Exam Questions

Coming soon

Flashcards

Flip through flashcards to lock it in.

Lesson

Coming soon

Ask Sage

Get help from Sage on this topic.

Learning Objectives

5.5.1.3 The energy change of reactions (HT only)

Content	Key opportunities for skills development
$During a chemical reaction: energy must be supplied to break bonds in the reactants energy is released when bonds in the products are formed. The energy needed to break bonds and the energy released when bonds are formed can be calculated from bond energies. The difference between the sum of the energy needed to break bonds in the reactants and the sum of the energy released when bonds in the products are formed is the overall energy change of the reaction. In an exothermic reaction, the energy released from forming new bonds is greater than the energy needed to break existing bonds. In an endothermic reaction, the energy needed to break existing bonds is greater than the energy released from forming new bonds.$
$Students should be able to calculate the energy transferred in chemical reactions using bond energies supplied.$	$MS 1a$

Content

Key opportunities for skills development

During a chemical reaction: energy must be supplied to break bonds in the reactants energy is released when bonds in the products are formed. The energy needed to break bonds and the energy released when bonds are formed can be calculated from bond energies. The difference between the sum of the energy needed to break bonds in the reactants and the sum of the energy released when bonds in the products are formed is the overall energy change of the reaction. In an exothermic reaction, the energy released from forming new bonds is greater than the energy needed to break existing bonds. In an endothermic reaction, the energy needed to break existing bonds is greater than the energy released from forming new bonds.

Students should be able to calculate the energy transferred in chemical reactions using bond energies supplied.

MS 1a