M.Elizabeth Chemistry 2010-2011
Spring Semester March 8 - March 21
Chemical Reaction Rates and Equilibrium
- GUHS Chemical Reaction Rates and Equilbrium SG word
- Kinetics Equilibrium Bell Ringer Part 1 Part 2 Part 3 Part 4 Part 5
- Kinetics Online Quiz 1 Equilibrium Online Quiz 2
- Reaction Rate Standard Notes word
- Equilibrium Standard Notes word
- Equilibrium Notes word
- Glencoe Kinetics ppt
- Reaction Rate ppt
- Glencoe Equilibrium ppt
- Kinetics and Equilibrium 2011 ppt
Mark Rosengarten Rate Of Reaction music video
Mark Rosengarten Equilibrium Shifts music video
Reaction Rate Video Notes
Equilibrium Video - Notes Taking Guide pdf
- Lab: Equilibrium Datasheet pdf
- Lab: Le Chatelier’s Principle pdf
- Calculating Keq pdf
- Le Chatelier’s Principle pdf
>> Reaction Rate Crossword word
>> Equilibrium Constant and Calculations word
>> LeChatelier's Principle Practice word
>> Collision Theory Questions word
>> Rate Graphing and Analysis Practice word
Online Resources (Web Sites)
Chemical Kinetics link
Kinetics with Canadian Connections link
8. Chemical reaction rates depend on factors that influence the frequency of collision of reactant molecules. As a basis for
understanding this concept:
a. the rate of reaction is the decrease in concentration of reactants or the increase in concentration of products with time.
b. reaction rates depend on such factors as concentration, temperature, and pressure.
c. catalysts increases the reaction rate. A catalyst increases the rate of a chemical reaction without taking part in the net
reaction. A catalyst lowers the energy barrier between reactants and products by promoting a more favorable pathway for the
reaction. Surfaces often play important roles as catalysts for many reactions. One reactant might be temporarily held on the
surface of a catalyst. There the bonds of the reactant may be weakened, allowing another substance to react with it more quickly.
Living systems speed up life-dependent reactions with biological catalysts called enzymes.
Chemical equilibrium is a dynamic process that occurs when there is not changes in a product or reactant concentration that
undergo reversible reactions with several factors affecting equilibrium that must be considered when writing expressions used to
quantify a state of equilibrium. Changes in heat accompanying chemical reactions and spontaneity of chemical reactions are key
topics, along with physical states of substances undergoing chemical reactions, for example gases respond to changes in pressure
and volume. Calculation of concentration and molarity for solutions, particularly for aqueous solutions and use of exponents are
needed to solve quantitative problems.
When a stress is applied to a chemical reaction in equilibrium, a shift will occur to partly relieve the stress.
9. Chemical equilibrium is a dynamic process at the molecular level. As a basis for understanding this concept: a. Students know
how to use Le Chatelier’s principle to predict the effect of changes in concentration, temperature, and pressure. Le Chatelier’s
principle can be introduced by emphasizing the balanced nature
of an equilibrium system. If an equilibrium system is stressed or disturbed, the system will respond (change or shift) to partially
relieve or undo the stress. A new equilibrium will eventually be established with a new set of conditions. When the stress is
applied, the reaction is no longer at equilibrium and will shift to regain equilibrium.
For instance, if the concentration of a reactant in a system in dynamic equilibrium is decreased, products will be consumed to
produce more of that reactant. Students need to remember that heat is a reactant in endothermic reactions and a product in
exothermic reactions. Therefore, increasing temperature will shift an endothermic reaction, for example, to the right to regain
equilibrium. Students should note that any endothermic chemical reaction is exothermic in the reverse direction.
Pressure is proportional to concentration for gases; therefore, for chemical reactions that have a gaseous product or reactant,
pressure affects the system as a whole. Increased pressure shifts the equilibrium toward the smaller number of moles of gas,
alleviating the pressure stress. If both sides of the equilibrium have an equal number of moles of gas, increasing pressure does
not affect the equilibrium. Adding an inert gas, such as argon, to a reaction will not change the partial pressures of the reactant or
product gases and therefore will have no effect on the equilibrium.
9. b. Students know equilibrium is established when forward and reverse reaction rates are equal.
Forward and reverse reactions at equilibrium are going on at the same time and at the same rate, causing overall concentrations
of each reactant and product to remain
constant over time.
9. c.* Students know how to write and calculate an equilibrium constant expression for a reaction.
Because the concentrations of substances in a system at chemical equilibrium are constant over time, chemical expressions
related to each concentration will also be constant. Here is a general equation for a reaction at equilibrium:
aA + bB ↔ c C + d D
The general expression for the equilibrium constant of a chemical reaction is Keq, defined at a particular temperature, often 25°
C. Its formula is