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Section 7–4: Reaction Rates. Physical Science Coach Kelsoe Pages 212–215. Objectives. Interpret chemical equations in terms of reactants, products, and conservation of mass. Balance chemical equations by manipulating coefficients.
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Section 7–4:Reaction Rates Physical Science Coach Kelsoe Pages 212–215
Objectives • Interpret chemical equations in terms of reactants, products, and conservation of mass. • Balance chemical equations by manipulating coefficients. • Convert between moles and mass of a substance using molar mass. • Calculate amounts of reactants or products by using molar mass, mole ratios, and balanced chemical equations.
Reactions Over Time • A reaction rate is the rate at which reactants change into products over time. • Reaction rates tell you how fast a reaction is going.
Reaction rates do NOT tell you how fast ______. A: substances are changing state • In general, if the temperature of a chemical reaction is increased, the reaction rate _______. A: increases • A log is burning in a fireplace. If the amount of oxygen reaching the log is decreased, which of the following statements is true? A: the reaction rate decreases.
Measuring how quickly a reactant disappears is one way to measure the rate of the reaction. • A chunk of limestone, which is calcium carbonate, reacts with acid at a certain rate. If the limestone were crushed, the rate of reaction between the acid and limestone would increase. • A catalyst is used in a catalytic converter in vehicles to help control pollution. For example, the catalytic converter speeds up the rate at which carbon monoxide is oxidized to carbon dioxide. (2CO + O2 2CO2)
Vocabulary • Reaction rate • Catalyst
Study Guide • #21-23, 42-44 should be completed.
Section 7–5:Equilibrium Physical Science Coach Kelsoe Pages 216–219
Objectives • Interpret chemical equations in terms of reactants, products, and conservation of mass. • Balance chemical equations by manipulating coefficients. • Convert between moles and mass of a substance using molar mass. • Calculate amounts of reactants or products by using molar mass, mole ratios, and balanced chemical equations.
When the forward and reverse paths of a change occur at the same rate, A: the system is in equilibrium. • The equation 2NO2 N2O4 shows a system ____. A: in chemical equilibrium. • The reaction H2CO3 + H2O H3O+ + HCO3- takes place in water. What happens to the equilibrium when the pressure is increased? A: it does not change.
The statement that when a change is introduced to a system in equilibrium, the equilibrium shifts in the direction that relieves the stress on the system is known as Le Chatelier’s principle. • Many manufacturing processes involve chemical reactions that reach equilibrium. One way to increase the amount of product formed is to decrease the concentration of the product in the system.
Vocabulary • Equilibrium • Reversible reaction
Study Guide • #24-26, 45-46 should be completed.