Reaction Rates and equilibrium

Consider the reaction.At 298 K, the equilibrium concentration of O2 is 1.6 x 10-2 M, and the equilibrium concentration of O3 is 2.86 x 10-28 M. What is the equilibrium constant of the reaction at this temperature?

2.0x10 -50

Consider the reaction below.At 500 K, the reaction is at equilibrium with the following concentrations.[PCI5]= 0.0095 M[PCI3] = 0.020[CI2] = 0.020 MWhat is the equilibrium constant for the given reaction? 0.042 0.42 2.4 24

A. 0.042

Which statement describes a heterogeneous catalyst? It is in a different phase than the reactants. It is in the same phase as the reactants. It increases the activation energy of a reaction. It lowers the reaction rate.

A. It is in a different phase than the reactants.

Consider the energy diagram below.Which statement best describes the diagram? The catalyzed reaction passes through C. The energy of the catalyst is shown by A. The reaction pathway through B is faster. The energy of the reactants with catalyst is at D.

A. The catalyzed reaction passes through C.

Consider the diagram below.What does D represent? energy of the products energy of the reactants reactants, Q + R products, N + M

A. energy of the products

The diagram below shows the movement of particles.What does this piece of evidence best support? the collision theory the Maxwell-Boltzmann distribution the effect of pressure on reaction rates the effect of temperature on reaction rates

A. the collision theory

Consider the reaction.At equilibrium, the concentrations of the different species are as follows.[NH3] = 0.105 M[N2] = 1.1 M[H2] = 1.50 MWhat is the equilibrium constant for the reaction at this temperature? 0.0030 0.030 34 340

A. 0.0030

Consider the reaction.At equilibrium, the concentrations of the different species are as follows.[H2O] = 0.077 M[Cl2O] = 0.077 M[HClO] = 0.023 MWhat is the equilibrium constant for the reaction at this temperature? 0.089 0.26 3.9 11

A. 0.089

Consider the reaction.At equilibrium, the concentrations are as follows.[NOCl] = 1.4 ´ 10-2 M[NO] = 1.2 ´ 10-3 M[Cl2] = 2.2 ´ 10-3 MWhat is the value of Keq for the reaction expressed in scientific notation? 1.6 ´ 10-5 6.2 ´ 10-4 6.2 ´ 104 1.6 ´ 105

A. 1.6 ´ 10-5

Consider the reaction.At equilibrium at 600 K, the concentrations are as follows.[HF] = 5.82 x 10-2 M[H2] = 8.4 x 10-3 M[F2] = 8.4 x 10-3 MWhat is the value of Keq for the reaction expressed in scientific notation? 2.1 x 10-2 2.1 x 102 1.2 x 103 1.2 x 10-3

A. 2.1 x 10-2

Which statement best describes an effect of using a catalyst in an industrial process? It lowers energy requirements. It increases waste. It increases toxic exhaust. It lowers production rates.

A. It lowers energy requirements.

Consider the reaction pathway graph below.Which of the following explains the importance of the activation energy acting as a barrier for reactants? It prevents most reactions from occurring spontaneously. It ensures the activated complexes remain stable. It allows energy to be released slowly from products. It stops the activated complexes from ever forming.

A. It prevents most reactions from occurring spontaneously.

Which applies to the collision theory? Particles need to collide in order to react. Particles may obtain successful collisions in any molecular orientation. Temperature increase causes kinetic energy of particles to decrease. Reactions do not have to begin with collision of molecules or particles.

A. Particles need to collide in order to react.

Consider the following chemical reaction in equilibrium.CH3COOH CH3COO-(aq) + H+(aq)What will happen to the chemical equilibrium if MgCl2 is added? The chemical equilibrium of the system will be unaffected. The chemical equilibrium of the system will shift to the right to favor the forward reaction. The chemical equilibrium of the system will shift to the left to favor the reverse reaction. The chemical equilibrium of the system will be damaged irreversibly.

A. The chemical equilibrium of the system will be unaffected.

According to Le Chatelier's principle, what happens when the concentration of a product is reduced in a chemical reaction that was in equilibrium? The equilibrium shifts to the right to favor the formation of products. The equilibrium shifts to the left to favor the formation of reactants. The equilibrium shifts in the exothermic direction. The equilibrium shifts in the endothermic direction.

A. The equilibrium shifts to the right to favor the formation of products.

Consider the following chemical reaction of bromothymol blue indicator. It appears yellow in undissociated form and blue in its dissociated aqueous solution. HC2H3O2(aq) H+(aq) + C2H3O2-(aq)yellow blueWhat will be the color of the solution if a large amount of H2CO3 is added? The solution will remain yellow. The solution will turn blue. The solution will turn pink. The solution will turn green.

A. The solution will remain yellow.

Consider the diagram below.What does C represent? enthalpy of reaction activation energy activated complex energy of the reactants

A. enthalpy of reaction

Consider the reaction pathway graph below.Which kind of reaction does this graph represent? exothermic because Hrxn = -167 kJ exothermic because Hrxn = 167 kJ endothermic because Hrxn = -1,083 kJ endothermic because Hrxn = 1,083 kJ

A. exothermic because Hrxn = -167 kJ

Consider the reaction pathway graph below.What is represented by D in the graph? the activation energy the enthalpy of the reaction the energy of the products the energy of the reactants

A. the activation energy

Reactions cannot occur without a certain minimum amount of energy. What is this minimum amount of energy called? the activation energy the activated complex the kinetic energy of reactants the potential energy of products

A. the activation energy

A reaction is shown below.Reaction : What can be concluded about this reaction? A homogeneous catalyst is being used in the reaction. A heterogeneous catalyst is being used in the reaction. A catalyst is not being used in this reaction. An enzyme is being used in this reaction.

B. A heterogeneous catalyst is being used in the reaction.

Although expensive, platinum is used as a catalyst to break down harmful gases in car exhaust into less harmful gases. Which statement best describes platinum in this use? It is a homogeneous catalyst, so only a small amount is needed even though it exits with the products. It is a heterogeneous catalyst, so only a small amount is needed and it is easily separated from the products. It is a homogeneous catalyst, so although a large amount is needed, it is easily separated from the products. It is a heterogeneous catalyst, so a large amount is needed and it exits with the products.

B. It is a heterogeneous catalyst, so only a small amount is needed and it is easily separated from the products.

Which will cause an increase in the reaction rate between molecules? Molecules have strong internal bonding. Molecules collide more frequently. Electrons in the bonds remain in a meta-stable state. Electrons do not have enough energy to leave the bonds.

B. Molecules collide more frequently.

Which topic is commonly used to explain activation energy and how chemical reactions happen? reaction rate collision theory velocity distribution spontaneous reaction

B. collision theory

Consider the reaction H2(g) + I2(g) 2HI(g). What is the reaction quotient, Q, for this system when [H2] = 0.100 M, [I2] = 0.200 M, and [HI] = 3.50 M? 87.5 175 350 613

B. 175 MARKED WITH x but not counted wrong

Carbon monoxide (CO) reacts with hydrogen (H2) to form methane (CH4) and water (H2O).The reaction is at equilibrium at 1,000 K. The equilibrium constant of the reaction is 3.90. At equilibrium, the concentrations are as follows.[CO] = 0.30 M[H2] = 0.10 M[H2O] = 0.020 MWhat is the equilibrium concentration of CH4 expressed in scientific notation? .0059 5.9 x 10-2 0.059 5.9 x 102

B. 5.9 x 10-2

What advantage does a heterogeneous catalyst provide over a homogeneous catalyst in industrial processes? A heterogeneous catalyst provides a higher reaction rate. A heterogeneous catalyst can be easily separated from reactants. A heterogeneous catalyst raises the activation energy higher. A heterogeneous catalyst provides an alternate reaction pathway.

B. A heterogeneous catalyst can be easily separated from reactants.

Consider the energy diagram below.xn.Which line indicates a higher reaction rate? A because it has a lower activation energy. B because it has a lower activation energy. A because its Grxn is much lower. B because its Grxn is much lower.

B. B because it has a lower activation energy.

A solid reactant is placed into a beaker of a warm water. The liquid vigorously bubbles as the solid dissolves into the solution. What will most likely happen if the temperature of the liquid is slightly reduced? More bubbles will be produced because the solution is becoming more concentrated. Fewer bubbles will be produced because of fewer collisions of reactant molecules. The solid will get smaller at a faster rate because of more collisions of reactant molecules. The solid will get larger at a slower rate because precipitate is coming out of the solution.

B. Fewer bubbles will be produced because of fewer collisions of reactant molecules.

Which statement is usually true about the relationship between activation energy and reaction rates? Low activation energy barriers result in low rates. High activation energy barriers result in low rates. Low activation energy barriers result in no reaction. High activation energy barriers result in no reaction.

B. High activation energy barriers result in low rates.

Consider the chemical equation in equilibrium.A(g) + 2B(g) C(g) + D(g) + heatWhat will happen to the equilibrium of this reaction if the temperature is increased? It will shift to the left because heat is released. It will shift to the left because heat is absorbed. It will shift to the right because heat is released. It will shift to the right because heat is absorbed.

B. It will shift to the left because heat is absorbed.

Which catalyzed reaction breaks up ozone? 2H2O2(l) 2H2O(l) + O2 O3 + O 2O2 2H2O2 (aq) 2H2O(l) + O2 O2 + 2SO2 2SO3

B. O3 + O 2O2

According to Le Chatelier's principle, which statement is true? The equilibrium constant is unchanged by temperature changes. The equilibrium constant changes with a change in temperature. The equilibrium constant increases with the concentration of reactants. The equilibrium constant decreases with the concentration of products.

B. The equilibrium constant changes with a change in temperature.

Which statement best describes the use of catalytic converters in automobiles? They decrease the rate of the reactions that produce harmful gases. They oxidize hydrocarbons to form less toxic gases. They combine the larger hydrocarbon molecules with smaller ones. They increase reaction temperature for cleaner burning.

B. They oxidize hydrocarbons to form less toxic gases.

Consider the reaction pathway graph below.Which kind of reaction does this graph represent? endothermic because Hrxn = -876.8 kJ endothermic because Hrxn = 876.8 kJ exothermic because Hrxn = -1,099.6 kJ exothermic because Hrxn = 1,099.6 kJ

B. endothermic because Hrxn = 876.8 kJ

Which lists all of the substances that appear in equilibrium constant expressions? pure gas and pure liquid pure gas and aqueous solution pure solid and pure liquid aqueous solution and pure liquid

B. pure gas and aqueous solution

Which statement describes a catalyst? Catalysts appear as reactants in a chemical equation. Catalysts are completely consumed by the reaction. Catalysts provide a lower energy pathway for the reaction. Catalysts speed up chemical reactions by increasing surface area.

C. Catalysts provide a lower energy pathway for the reaction.

Which statement defines activation energy? It is the sum of the maximum energy and reactant energy. It is the sum of the product energy and reactant energy. It is the difference between reactant energy and maximum energy. It is the difference between product energy and reactant energy.

C. It is the difference between reactant energy and maximum energy.

Which best explains why sawdust burns more quickly than a block of wood of equal mass under the same conditions? The molecules move more quickly in the sawdust than in the block of wood. The pressure of oxygen is greater on the sawdust. More molecules in the sawdust can collide with oxygen molecules. Oxygen is more concentrated near the sawdust than the block of wood.

C. More molecules in the sawdust can collide with oxygen molecules.

The production of water proceeds according to the following equation.2H2(g) + O2(g) 2H2O(g)Which describes a way to speed up the collisions between hydrogen and oxygen molecules to produce more water? Use a less-intense source of heat on the reactants. Maintain the same temperature of the reactants. Place the reactants in a smaller container. Reduce the concentration of the reactants.

C. Place the reactants in a smaller container.

Which statement best describes how to read a reaction pathway graph for an endothermic reaction? Reactants absorb a minimum amount of energy and then release a larger amount of energy as products form. Reactants release a minimum amount of energy and then absorb a larger amount of energy as products form. Reactants absorb a minimum amount of energy and then release a smaller amount of energy as products form. Reactants release a minimum amount of energy and then absorb a smaller amount of energy as products form.

C. Reactants absorb a minimum amount of energy and then release a smaller amount of energy as products form.

Consider the equilibrium system below.If the system is at dynamic equilibrium, which statement is true? Sublimation of the NH4CI crystals stops. Solidification of the NH4CI vapors stops. The rate of sublimation of the NH4CI crystals is equal to the rate of solidification of the NH4CI vapors. The rate of sublimation of the NH4CI crystals is higher than the rate of solidification of the NH4CI vapors.

C. The rate of sublimation of the NH4CI crystals is equal to the rate of solidification of the NH4CI vapors.

Consider the reaction below.H2(g) + CO2(g) H2O(g) + CO(g)At equilibrium at 600 K, the following are true. [CO2] = 9.5 x 10-4 M[H2] = 4.5 x 10-2 M[H2O] = 4.6 x 10-3 M[CO] = 4.6 x 10-3 MWhat is the value of the equilibrium constant for this reaction in correct scientific notation? 4.9 x 10-3 4.9 x 10-2 4.9 x 10-1 4.9 x 103

C. 4.9 x 10-1

According to Le Chatelier's principle, what always happens to the equilibrium of a reaction when the temperature is reduced? It shifts to the right. It shifts to the left. It shifts in the exothermic direction. It shifts in the endothermic direction.

C. It shifts in the exothermic direction.

Consider the reaction in chemical equilibrium. COCl2(g) CO(g) + Cl2(g)Which is the correct equation for K?

C. K = [CO][Cl2] / [COCl2]

Consider the following chemical reaction at equilibrium.H2SO4(aq) 2H+(aq) + SO42-(aq)The addition of which compound will cause a shift in equilibrium because of a common ion effect? NaCl KNO3 MgSO4 FeCl3

C. MgSO4

According to Le Chatelier's principle, a change in pressure affects the chemical equilibrium of the reaction system under what condition? The reactants and the products are in the solid phase. The reactants and the products are in the liquid phase. Some of the reactants or the products are in the gaseous phase. Some of the reactants or the products are solid, and some are liquid.

C. Some of the reactants or the products are in the gaseous phase.

Consider the chemical equilibrium of the reaction.AgCl(s) Ag+(aq) + Cl-(aq)What will happen to the chemical equilibrium if AgNO3 is added? There is no shift in the chemical equilibrium of the system. The chemical equilibrium of the system shifts to the right. The chemical equilibrium of the system shifts to the left. The chemical equilibrium of the system is destroyed.

C. The chemical equilibrium of the system shifts to the left.

According to Le Chatelier's principle, what happens to the equilibrium constant (K) when the concentration of the reactants is doubled? The value of the equilibrium constant (K) is doubled. The value of the equilibrium constant (K) is halved. The value of the equilibrium constant (K) remains the same. The value of the equilibrium constant (K) changes unpredictably.

C. The value of the equilibrium constant (K) remains the same.

Why does platinum metal make a good catalytic surface for reactant molecules? It causes reactant molecules to be less reactive. It strengthens bonds between reactant molecules. It prevents products from breaking away from the surface. It holds reactant molecules in a good position for them to react.

D. It holds reactant molecules in a good position for them to react.

Which statement best describes the use of a catalyst in a fuel cell? It reduces waste. It lowers energy requirements. It reduces toxic exhaust. It increases reaction rates.

D. It increases reaction rates.

Which description explains the role of activation energy in a chemical reaction? It provides useful energy that is released in an exothermic reaction. It stops the products from being formed from the intermediate state. It slows down the overall chemical reaction so it does not happen too quickly. It provides reactants with sufficient energy for bonds to break and reform.

D. It provides reactants with sufficient energy for bonds to break and reform.

Which statement best describes the reaction pathway graph for endothermic reactions? mainly downhill always linear always parabolic mainly uphill

D. mainly uphill

Hydrogen gas reacts rapidly with oxygen gas in the presence of a platinum catalyst. Which equation correctly represents this reaction?

D. 2 H2(g) + O2 (g) -->pt 2H2O(g)

Consider the reaction pathway graph below.Which inference is supported by evidence in the graph? A and C show that the reaction enthalpy is less than the activation energy. G and E show that this reaction is an endothermic process with heat release. B and F show that the activated complex has less energy than the reactants. E and D show that the energy of the products is less than that of the reactants.

D. E and D show that the energy of the products is less than that of the reactants.

Consider the reaction pathway graph below.Which statement accurately describes this graph? It represents an endothermic reaction because the products have more energy than the reactants. It represents an exothermic reaction because the products have more energy than the reactants. It represents an endothermic reaction because the reactants have more energy than the products. It represents an exothermic reaction because the reactants have more energy than the products.

D. It represents an exothermic reaction because the reactants have more energy than the products.

Which represents the correct equilibrium constant expression for the reaction below?

D. Keq Cu2+ / Ag+2

Consider the reaction pathway graph below.Which conclusion can be accurately drawn from the graph? Hrxn for the complete reaction is negative, but Ea is positive. Hrxn for the complete reaction is positive, but Ea is negative. The breakdown of ozone is an exothermic process. The breakdown of ozone is an endothermic process.

D. The breakdown of ozone is an endothermic process.

Consider the chemical equation in equilibrium. 2H2(g) + O2(g) 2H2O(g)What will happen if the pressure of the system is increased? The reaction will not change. The reverse reaction will be favored. The reaction will stop completely. The forward reaction will be favored.

D. The forward reaction will be favored.

Consider the reaction below.C2H4(g) + H2(g) C2H6(g)Which change would likely cause the greatest increase in the rate of the reaction? decrease temperature and decrease pressure increase temperature and decrease pressure decrease temperature and increase pressure increase temperature and increase pressure

D. increase temperature and increase pressure

Which definition describes activation energy? the speed at which reactants form products in a chemical reaction the short-lived, high-energy intermediate between reactants and products the diagram showing a change in energy between reactants and products the minimum energy that a set of reactants must attain before reaction can occur

D. the minimum energy that a set of reactants must attain before reaction can occur

What overall effect does adding a catalyst have on a chemical reaction? It slows the reaction. It speeds up the reaction. It reduces the concentration of products. It increases the concentration of reactants.

It speeds up the reaction

Sulfuric acid was once produced through the reaction of sulfur trioxide with water. Sulfur trioxide can form through the reaction of sulfur dioxide and oxygen gas. When nitrogen monoxide gas is added to the system, the reaction speeds up significantly because it proceeds through the following steps: Identify the catalyst in this reaction, explain how you know it is the catalyst, and describe how it increases the rate of the reaction.

NO is the catalyst. NO is the catalyst because it increases the rate of the reaction but is not consumed during the reaction. NO increases the rate of the reaction by lowering the activation energy. The reaction of NO with O2 provides an alternative reaction pathway with a lower activation energy.

Consider the reaction below.What is the most likely effect to the forward reaction if there is an increase in pressure on this reaction? The reactant surface area increases. The reaction rate decreases. The reaction is not affected at all. The reaction stops completely.

NOT C - The reaction is not affected at all.

Consider the following reversible reaction.What is the equilibrium constant expression for the given system?

NOT c

The enzyme urease catalyzes this reaction. If urease is added to a solution that contains ammonia and other nitrogen-containing compounds (but no urea), will the urease catalyze any reactions? Explain your answer. Which of the following did your answer include? Urease is an enzyme. Enzymes are highly specific in the reactions they catalyze. Enzymes can typically bind only to the substrate(s) for the reaction they catalyze. If the solution contains no urea, urease will not bind to any of the substances in the solution, so it will not catalyze any reactions in the solution.

Urease is an enzyme. Enzymes are highly specific in the reactions they catalyze. Enzymes can typically bind only to the substrate(s) for the reaction they catalyze. If the solution contains no urea, urease will not bind to any of the substances in the solution, so it will not catalyze any reactions in the solution.

Consider the chemical equilibrium of the reaction. NH4OH(aq) NH4+(aq) + OH(aq) What will happen to the chemical equilibrium if NH4Cl is added to this solution? The chemical equilibrium will shift to the right. The chemical equilibrium will not shift. The chemical equilibrium will shift to the left. The chemical equilibrium will be lost.

c. The chemical equilibrium will shift to the left.