Chapter 2 Chemistry Chapter 2 Chemistry Section 2-2 Energy Be Able To Describe the physical properties of each state of matter. Describe the role of reactants and products in chemical reactions. Explain the relationship between enzymes and activation energy. Explain how oxidation and reduction reactions are linked. Key Terms Key Terms: Pg 35.

Energy and Matter EnergyEnergy is the ability to do work or cause change. Free energyFree energy is the energy that is available for work. As energy flows through a single organism it may change form. Atoms are in constant motion all of the time. stateThe rate at which atoms move is determined by matter’s state: solid, liquid, or a gas. Do these McGriddles supply energy?

Energy and Chemical Reactions reactants productsIn a chemical equation reactants are shown on the left and the products are shown on the right. The arrow indicates the direction of the reaction (double arrow means it can proceed either way). CO 2 + H 2 O H 2 CO 3 Exergonic reactions endergonic reactionsExergonic reactions release free energy and endergonic reactions absorb free energy. activation energyThe amount of energy needed to start a chemical reaction is activation energy. CatalystsenzymeCatalysts, such as an enzyme, reduce activation energy.

Energy and Chemical Reactions redox-reactionA redox-reaction is a reaction in which electrons are transferred between atoms. oxidation reactionIn an oxidation reaction a reactant loses one or more electrons (e.g. Na becomes Na + ) reduction reactionIn a reduction reaction a reactant gains one or more electrons (e.g. Cl becomes Cl - ) Redox reactions always occur together. Which atom above has been oxidized and which has been reduced?