# Chapter 18 Reaction Rates And Equilibrium

42 Questions  I  By Verdun
Chapter 18 REACTION RATES AND EQUILIBRIUM

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 1 How are rates of chemical change expressed?
 A. Rates of chemical change are usually expressed as the amount of energy changing per unit time.
 B. Rates of chemical change are usually expressed as the amount of non- reactant changing per unit time.
 C. Rates of chemical change are usually expressed as the amount of reactant changing per unit time.
 2 Look at Figure 18.3 on page 542. In a typical reaction, as time passes, the amount of____________ decreases and the amount of ____________ increases.
 A. Reactant, product
 B. Cataltyst, energy
 C. Inhibitor, equilibrium
 3 What does collision theory say about atoms, ions, ormolecules reacting to  form products when they collide?
 A. Collision theory states that the particles must have enough kinetic energy when they collide to form products.
 B. Collision theory states that the particles must have enough potential energy when they collide to form products.
 C. Collision theory states that the particles must have enough no kinetic energy when they collide to form products.
 4 Particles lacking the necessary kinetic energy to react bounce apart ____________ when they collide.
 A. Reactant
 B. Changed
 C. Unchanged
 5 Look at Figure 18.5 on page 543. Which arrangement of atoms contains the least amount of energy?
 A. Reactants
 B. Activated complex
 C. Products
 6 Circle the letter of the term that completes the sentence correctly. The minimum amount of energy that particles must have in order to react is called the _______ .
 A. Kinetic energy
 B. Activation energy
 C. Potential energy
 D. Collision energy
 7 An activated complex is the arrangement of atoms at the ______________________ of the activation-energy barrier.
 A. Product
 B. Reactant
 C. Peak
 8 Circle the letter of the term that best describes the lifetime of an activated complex.
 A. 10–15 s
 B. 10 13 s
 C. 10–13 s
 D. 10–1 s
 9 Why is an activated complex sometimes called the transition state?
 A. It is called the transition state because an activated complex is unstable and is as likely to re-form reactants as it is to form products.
 B. It is called the transition state because an activated complex is stable and is as likely to re-form reactants as it is to form products.
 C. It is called the transition state because an activated complex is unstable and is as likely to re-form reactants as it is to form reactant.
 10 Changes in the rate of chemical reactions depend on conditions such as
 A. Reactant, product, and activation
 B. Temperature, concentration, and particle size
 C. Collision, intervals, and kenetic energy
 11 The main effect of increasing the temperature of a chemical reaction is to ______________________ the number of particles that have enough kinetic energy to react when they collide.
 A. Increase
 B. Decrease
 C. Interpret
 12 What happens when you put more reacting particles into a fixed volume?
 A. The concentration of reactants increases, the collision frequency increases, and, therefore, the reaction rate decreases.
 B. The concentration of reactants increases, the collision frequency increases, and, therefore, the reaction rate increases.
 C. The concentration of reactants decreases, the collision frequency increases, and, therefore, the reaction rate increases.
 13 The smaller the particle size, the larger the surface area of a given _____________.
 A. Absorbant of a particle.
 B. Mass of a particle.
 C. Release of a particle.
 14 What are some ways to increase the surface area of solid reactants?
 A. One way is to dissolve the solid; another way is to grind the solid into a fine powder.
 B. One way is to leave it as a solid; another way is to make it into a liquid.
 C. One way is to make into a vapor; another way is to change it into rough powder.
 15 A ______________________ is a substance that increases the rate of a reaction without being used up itself during the reaction.
 A. Product
 B. Reactant
 C. Catalyst
 16 What does a catalyst do?
 A. A catalyst permits reactions to proceed at a higher energy than is normally required. A catalyst lowers the activation energy.
 B. A catalyst permits reactions to proceed at a lower energy than is normally required. A catalyst raises the activation energy.
 C. A catalyst permits reactions to proceed at a lower energy than is normally required. A catalyst lowers the activation energy.
 17 In a chemical equation, how do you show that catalysts are not consumed or chemically altered during a reaction?
 A. The catalyst is often written above the stop arrow in the equation.
 B. The catalyst is often written below the yield arrow in the equation.
 C. The catalyst is often written above the yield arrow in the equation.
 18 A(n) ______________________ is a substance that interferes with the action of a catalyst.
 A. Particle size
 B. Reactant
 C. Inhibitor
 19 What happens in reversible reactions?
 A. In reversible reactions, two opposite products occur simultaneously.
 B. In reversible reactions, two opposite reactions occur simultaneously.
 C. In reversible reactions, two of the same reactions occur simultaneously.
 20 Chemical equilibrium is a stateof balance in which the rates of forward and reverse reactions __________; no net change in the amount of reactants and products occurs in the chemical system.
 A. Not equal
 B. Are equal
 C. The same at some points
 21 The equilibrium position of a reaction is given by the relative_______________ of the system’s components at equilibrium.
 A. Pressure
 B. Concentration
 C. Temperature
 22 At equilibrium, how many types of molecules are present in
 A. 3
 B. 6
 C. 9
 23 What is Le Châtelier’s principle?
 A. Le Châtelier’s principle states that if a stress is applied to a system in dynamic no equilibrium, the system changes to relieve the stress.
 B. Le Châtelier’s principle states that if a stress is applied to a system in dynamic equilibrium, the system changes to relieve the stress.
 C. Le Châtelier’s principle states that if a stress is applied to a system in dynamic equilibrium, the system stays the same to relieve the stress.
 24 Stresses that upset the equilibrium of a chemical system include changes in _______
 A. Kentic, potinial, and reactants
 B. Reactant, products, and balance
 C. Concentration, pressure, and temperature.
 25 When you add a product to a reversible chemical reaction, the reaction is always pushed in the direction of ______________________ .
 A. Products
 B. Reactants
 C. Equilbrium
 26 When you remove a product, the reaction is pulled in the direction of ______________________ .
 A. Products
 B. Reactanrs
 C. Equilbrium
 27 ______________ the temperature of achemical reaction causes the equilibrium position of a reaction to shift in the direction that absorbs heat.
 A. Stabilizing
 B. Increasing
 C. Decreasing
 28 How does increasing pressure affect a chemical system?
 A. An increase in pressure results in a shift in the equilibrium position that favors the formation of a smaller volume of gas.
 B. An increase in pressure results in a shift in the equilibrium position that favors the formation of a larger volume of gas.
 C. An increase in pressure results in a shift in the equilibrium position that favors the formation of a double the volume of gas.
 29 The equilibrium constant (Keq) is the ratio of ____________________ concentrations to ____________________ concentrations at equilibrium, with each concentration raised to a power equal to the number of ____________________ of that substance in the balanced chemical equation.
 A. Heat, product, reactant
 B. Reactant, product,heat
 C. Product, reactant, moles
 30 What are the exponents in the equilibrium-constant expression?
 A. The exponents are the coefficients from the balanced math equation.
 B. The exponents are the coefficients from the unbalanced chemical equation.
 C. The exponents are the coefficients from the balanced chemical equation.
 31 What do the square brackets indicate in the equilibrium-constant expression?
 A. The square brackets indicate the concentrations of substances in pounds per liter (mol/L).
 B. The square brackets indicate the concentrations of substances in moles per liter (mol/L).
 C. The square brackets indicate the concentrations of substances insuare moles per liter. (mol/L).
 32 The value of Keq for a reaction depend on the__________________.
 A. Mass
 B. Temperature
 C. Size
 33 A value of Keq greater than 1 means that ______________________ are favored over ______________________ .
 A. Reactant, mass
 B. Products, reactants
 C. Mass, product
 34 A value of Keq less than 1 means that ______________________ are favored over ______________________ .
 A. Reactant, product
 B. Products, reactants
 C. Reactant, mass
 35 Free energy is energy that is available to do ______________________ .
 A. Games
 B. Rest
 C. Work
 36 ________processes can be made 100% efficient.
 A. No
 B. All
 C. A special
 37 Spontaneous reactions are reactions that occur naturally and that favor the formation of ______________________ at the specified conditions.
 A. Bases
 B. Acids
 C. Products
 38 Some reactions that are nonspontaneous at one set of conditions may be spontaneous at other conditions.
 A. Acids
 B. Reactions
 C. Products
 39 Some factor other than ______________________ change must help determine whether a physical or chemical process is spontaneous.
 A. Moisture
 B. Cold
 C. Heat
 40 What is entropy?
 A. Entropy is the measure of ability of a system.
 B. Entropy is the measure of order of a system.
 C. Entropy is the measure of disorder of a system.
 41 The law of disorder states that processes move in the direction of ______________________ disorder or randomness.
 A. Median
 B. Minumum
 C. Maximum
 42 Does entropy tend to increase or decrease in chemical reactions in which the total number of product molecules is greater than the total number of reactant molecules? ______________________
 A. Entropy decreases
 B. Entropy increases
 C. Entropy stays the same
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