4/10/12 - Bellringer Explain what is happening at a molecular level when energy is added or removed.
Grade Worksheets
23.4 – Reaction Rates and Energy Part A
Objectives Identify the source of energy changes in chemical reactions. Compare and contrast endothermic and exothermic reactions.
Chemical Kinetics The area of chemistry concerned with the speed at which reactions occur
Collision Theory In order for reactants to form products the reactants must collide with enough energy to start the reaction (activation energy)
Energy Changes Chemical reaction involve energy exchange –Breaking chemical bonds requires energy –Forming chemical bonds releases energy
More Energy Out In exergonic reactions, the energy required to break bonds is less than the energy released from new bonds –The energy given off is usually light Exergonic - releases more than absorbs
Exothermic Reaction Give off energy in the form of heat
More Energy In In endergonic reaction, more energy is required to break bonds than to form new ones, energy is needed for the reaction to occur Endergonic – absorbs more than releases
Endothermic Reaction If the energy needed/absorbed is heat
In-Class Assignment/Homework DR WKT 23.4 RFN WKT –#2, 4, ONLY