The transformation of the reacting substances into products during a chemical reaction is accompanied by energy changes. The chemical processes are accompanied with release or absorption of energy as heat or light .

• Heat of reaction
• Exothermic and endothermic processes
• Hess's Law

• Theory
• Simulations
• Problems and tests

Theory

http://www.citycollegiate.com/title_chemistryixb.htm The site contains definitions and examples for types of chemical reactions. Exothermic and endothermic reactions are described in detail and graphically represented.

http://www.cornwallis.kent.sch.uk/intranet/elearn/science/ chemreact/exothermic_reactions.html Examples for exothermic reactions in the living organisms such as aerobic respiration, anaerobic respiration and fermentation.

http://misterguch.brinkster.net/energydiagram.html This site contains energy diagram for an exothermic reaction and definitions for reactants, products, activation energy, transition state and heat of reaction.

http://www.chem.ox.ac.uk/vrchemistry/energy/default.htm Examples for exothermic and endothermic reactions, which are defined as difference between the reactants and products energies.

http://www.wpbschoolhouse.btinternet.co.uk/page03/3_51energy.htm Heat Changes in Chemical Reactions.

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Simulations

http://cwx.prenhall.com/petrucci/medialib/media_portfolio/text_images/019_THERMITE.MOV A movie for the reaction between Fe2O3 and Al.

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Problems and tests