Chapter 10 Reaction Rates and Chemical Equilibrium Lecture Presentation Chapter 10 Reaction Rates and Chemical Equilibrium Karen C. Timberlake

Chapter 4 Reaction Rates and Chemical Equilibrium A neonatal nurse works with newborns that are premature or have birth defects, cardiac malformations, and surgical problems. Most neonatal nurses care for infants from the time of birth until the time they are discharged from the hospital.

Chapter 10 Readiness Key Math Skills Solving Equations (1.4D) Writing Numbers in Scientific Notation (1.4F) Core Chemistry Skills Using Significant Figures in Calculations (2.3) Balancing a Chemical Equation (7.1) Calculating Concentration (9.4)

10.1 Rates of Reactions Reaction rates vary greatly for everyday processes. A banana ripens in a few days, silver tarnishes in a few months, while the aging process of humans takes many years. Learning Goal Describe how temperature, concentration, and catalysts affect the rate of a reaction.

Rates of Reaction Reacting molecules must collide, have a minimum amount of energy, and have the proper orientation to form products.

Activation Energy Even when a collision has the proper orientation, there still must be sufficient energy to break the bonds between the atoms of the reactants. Three Conditions Required for a Reaction to Occur 1. Collision The reactants must collide. 2. Orientation The reactants must align properly to break and form bonds. 3. Energy The collision must provide the energy of activation.

Activation Energy The activation energy is the minimum amount of energy required to break the bonds between atoms of the reactants.

Rate of Reaction The rate (or speed) of a reaction is determined by measuring the amount of reactant used up in a certain period of time. product formed in a certain period of time.

Factors That Affect the Rate of a Reaction Reactions with low activation energies go faster than reactions with high activation energies. For any reaction, the rate is affected by changes in temperature. changes in reaction concentration. adding a catalyst.

Rate of Reaction: Temperature At higher temperatures the increase in kinetic energy of the reactant molecules makes them move faster. makes them collide more often. makes them collide with more energy. For every 10 °C increase in temperature, most reaction rates approximately double.

Rate of Reaction: Reactant Concentration When there are more reacting molecules, more collisions that form products can occur, and the reaction goes faster.

Rate of Reaction: Catalysts Adding a catalyst speeds up the rate of the reaction by providing an alternative pathway that has a lower activation energy. When activation energy is lowered, more collisions provide sufficient energy for reactants to form product. During a reaction, a catalyst is not changed or consumed.

Factors That Affect Reaction Rates

Study Check Indicate the effect of each factor listed on the rate of the reaction as (I) increases, (D) decreases, or (N) no change. 2CO(g) + O2(g)  2CO2 (g) A. raising the temperature B. removing O2 C. adding a catalyst D. lowering the temperature

Solution Indicate the effect of each factor listed on the rate of the reaction as (I) increases, (D) decreases, or (N) no change. 2CO(g) + O2(g)  2CO2 (g) A. raising the temperature (I) increases B. removing O2 (D) decreases C. adding a catalyst (I) increases D. lowering the temperature (D) decreases

Study Check State the effect of each on the rate of reaction as (I) increases, (D) decreases, or (N) no change. A. decreasing the temperature B. removing one of the reactants C. adding a catalyst D. placing the reaction flask in ice E. increasing the concentration of a reactant

Study Check State the effect of each on the rate of reaction as (I) increases, (D) decreases, or (N) no change. A. decreasing the temperature (D) decreases B. removing one of the reactants (D) decreases C. adding a catalyst (I) increases D. placing the reaction flask in ice (D) decreases E. increasing the concentration of a reactant (I) increases

Chemistry Link to the Environment: Catalytic Converters Catalytic converters are used in automobile engines to reduce pollutants such as carbon monoxide (CO), hydrocarbons such as octane (C8H18), and nitrogen oxide (NO).

Chemistry Link to the Environment: Catalytic Converters When pollutants pass through the surface, they react with the catalysts and are converted to CO2, N2, O2, and H2O.