Energy Level Diagrams
2 guided lessons · 18 checks · 3. Physical Chemistry → Energetics
Guided lessons for this note
Which concept don't you understand yet?
We'll explain it simply and check your understanding. Pick any lesson — any order works.
0 of 18 checks correct so far
Lesson 1 of 2
Reading the axes and arrows
An energy level diagram is a map of where the energy sits before and after a reaction. This lesson fixes the axes, the two levels and the arrow that tells you which way the heat flowed.
What you know already
From Exothermic & Endothermic you already know which reactions warm their surroundings and which cool them. This note draws that story as a picture, placing reactants and products on an energy axis so the direction of change can be read at a glance. Two carefully labelled sketches are all the exam asks for.
Key points of understanding
- An energy level diagram sets the energies of reactants and products side by side for comparison.
- Energy runs up the y-axis while the x-axis tracks how far the reaction has progressed.
- Arrows point downwards for exothermic reactions and upwards for endothermic ones.
- The height difference between reactants and products represents the overall enthalpy change.
- Reactants sit above products in exothermic reactions and below them in endothermic ones.
Energy level diagram of an exothermic reaction and an endothermic reaction
Choose a confidence level to continue.
Prefer to read it all at once? Show the full lesson as a page
1.Reading the axes and arrows
An energy level diagram is a map of where the energy sits before and after a reaction. This lesson fixes the axes, the two levels and the arrow that tells you which way the heat flowed.
Energy level diagram of an exothermic reaction and an endothermic reaction
Key points
- An energy level diagram sets the energies of reactants and products side by side for comparison.
- Energy runs up the y-axis while the x-axis tracks how far the reaction has progressed.
- Arrows point downwards for exothermic reactions and upwards for endothermic ones.
Guided content from the SME authoring corpus — note rn_HNXFQt7vM32g6PMv, pinned at 51a6ed34e715 · promoted SyllabAI/syllabai-resources e967e75f1339