REACTION RATES & FACTORS AFFECTING EQUILIBRIUM CHAPTER 3 ACTIVITY 5 REACTION RATES & FACTORS AFFECTING EQUILIBRIUM

Energy Diagrams 2H2 + O2 2H2O E of products A.E. E E of reactants Activated Complex Energy Reaction Progress A.E. (activation energy): minimum energy needed for a reaction to occur Activated Complex: transitional structure formed from an effective collision.

Not Every Collision Produces Products Reactants must: 1. Collide with the correct orientation 2. Have enough energy to produce products.

The Reaction Process Collision Theory: Explanation of reactions as a result of collisions. Particles must collide Particles must collide in the correct orientation Collision must be energetic enough to disrupt bonds

Catalyst A substance that increases the rate of reaction without being used up itself in the reaction. Energy barrier w/o catalyst Energy barrier w catalyst Reactants Energy Products Reaction Progress

Exothermic vs. Endothermic A process that loses heat to its surroundings. Fe2O3(s) + CO(g) Fe(s) + CO2(g) + 26.3 kJ Endothermic: A process that absorbs heat from its surroundings. 2NaHCO3(s) + 129 kJ Na2CO3(s) + H2O(g) + CO2(g)

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Is the following an example of an exothermic or endothermic reaction? Reactants Potential Energy EXOTHERMIC=energy is released Products Reaction Progress

Is the following an example of an exothermic or endothermic reaction? Products Potential Energy Reactants ENDOTHERMIC=energy is absorbed Reaction Progress

Factors Affecting Reaction Rates 1. Temperature 2. Concentration 3. Particle Size 4. Catalysts

Factors Affecting Reaction Rates 1. Temperature WHY Temp Rate Kinetic Energy

Factors Affecting Reaction Rates 2. Concentration WHY Conc. Rate More Particles increases collision frequency

Factors Affecting Reaction Rates 3. Particle Size WHY Particle Rate Smaller Particle Size size increases the surface area

Factors Affecting Reaction Rates 4. Catalyst WHY Adding a Rate Activation Energy Catalyst

FACTORS AFFECTING EQ. Le Chatelier’s Principle Reactions will stabilize and establish equilibrium. If this system is disturbed from equilibrium, it will shift in order to reduce the disturbance. When any of the following three things are changed, the system will change to re-establish equilibrium. Concentration Temperature Pressure System @ Equilibrium R P Systems not @ Equilibrium

Know the Difference Factors Affecting: Solubility Reaction Rates Equilibrium Temperature 2. Agitation 2. Concentration 3. Particle Size 3. Pressure 4. Catalyst

Concentration H2CO3 CO2 + H2O If we add CO2, more H2CO3 will be made If we remove CO2, more CO2 & H2O will be made

Concentration H2CO3 CO2 + H2O If we remove H2CO3, more H2CO3 will be made If we add H2CO3, more CO2 & H2O will be made

Temperature 2SO2 + O2 2SO3 + heat If we add heat, more reactants will be made in order to absorb the excess heat If we remove heat, more products will be made in order to replace the heat that has been removed.

Pressure Only Gases Are Affected! N2 + 3H2 2NH3 If we increase pressure, more products will be made (less moles) 4 moles If we decrease pressure, more reactants will be made (more moles) 2 moles

Review Reactions will stabilize and establish equilibrium. When any of the following three things are changed, the reaction will change to re-establish equilibrium. Concentration Temperature Pressure R = P