Contents

States of matter

Atoms, elements and compounds

Stoichiometry

Electrochemistry

ElectrolysisBeing prepared
Electrolysis of solutions and electroplatingBeing prepared
Fuel cellsBeing prepared

Chemical energetics

Chemical reactions

Acids, bases and salts

Acids, bases and indicators
OxidesBeing prepared
Making saltsBeing prepared

The Periodic Table

Reading the tableBeing prepared
Group I: the alkali metalsBeing prepared
Group VII: the halogensBeing prepared
Transition elements and noble gasesBeing prepared

Metals

Metals and alloysBeing prepared
The reactivity seriesBeing prepared
CorrosionBeing prepared
Extracting metalsBeing prepared

Chemistry of the environment

WaterBeing prepared
FertilisersBeing prepared
Air quality and climateBeing prepared

Organic chemistry

Naming organic moleculesBeing prepared
Crude oil and alkanesBeing prepared
AlkenesBeing prepared
Alcohols and carboxylic acidsBeing prepared
PolymersBeing prepared

Experimental techniques and chemical analysis

Mixtures and separation
Measuring and planning experimentsBeing prepared
Crystallisation
Distillation
Paper chromatography
Choosing methods and checking purityBeing prepared
TitrationBeing prepared
Gas testsBeing prepared
Anion testsBeing prepared
Cation and flame testsBeing prepared

Part 2 of 2

Page 02

Reaction pathway diagrams

deduce

Try it yourself

The diagram shows the reaction pathway diagram for burning ethanol. Which statement is correct?

deduce: reach a conclusion from the information given.

A reaction pathway diagram for burning ethanol. The reactants, C₂H₅OH + 3O₂, are on a high level on the left. A curve rises over a hump and falls to the products, 2CO₂ + 3H₂O, on a much lower level on the right.

Choose one answera.The curve rises in the middle, so the reaction is endothermicb.The products are lower, so the reaction takes in thermal energyc.The products have less energy than the reactants, so it is exothermicd.The products have more energy than the reactants, so it is endothermic

Your saved work

Answers, earlier attempts and your Pause and check notes stay in this browser. Export a copy to keep, to move to another device or to hand to your teacher. Importing a copy keeps your current answers and adds earlier attempts.

Import saved work

Scope and sources

Cambridge IGCSE Chemistry 0620 · 2026–2028 v2 · Original learning materials.

Energy changes in reactions (5.1 Core 1–3, Supplement 4–6): exothermic and endothermic reactions and the temperature of the surroundings, reaction pathway diagrams, the enthalpy change ΔH and its sign, activation energy, and drawing and labelling pathway diagrams. Bond breaking, bond making and bond energies are in the next module; collisions and catalysts in topic 6.

Apparatus, amounts and times in the experiment are illustrative. Real practical work follows a teacher-approved safety method.

Official Cambridge syllabus