| Select | | View | Download | | 33.1 System, surroundings and the Law of conservation of energy | | |
| 33.2 Enthalpy change of a reaction | | |
| 33.3 Exothermic and endothermic reactions in terms of enthalpy change | | |
| 33.4 Exothermic and endothermic reactions in terms of forming and breaking of chemical bonds | | |
| 33.1 System, surroundings and the Law of conservation of energy (bilingual version) | | |
| 33.2 Enthalpy change of a reaction (bilingual version) | | |
| 33.3 Exothermic and endothermic reactions in terms of enthalpy change (bilingual version) | | |
| 33.4 Exothermic and endothermic reactions in terms of forming and breaking of chemical bonds (bilingual version) | | |
| Energy changes in chemical reactions (combined version) | | |
| Energy changes in chemical reactions (bilingual, combined version) | | |