Test Yourself : Chapter 52 Activation energy

Which of the following statements concerning activation energy are correct?

(1) It is the energy barrier that the reactant particles have to overcome before a reaction can occur.

(2) A reaction has lower activation energy at a lower temperature.

(3) A faster reaction generally has lower activation energy.

• A. (1) and (2) only
• B. (1) and (3) only
• C. (2) and (3) only
• D. (1), (2) and (3)

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NGSS.HS-PS1-5

Which of the following statements concerning activated complex are correct?

(1) It is highly unstable.

(2) It contains partially broken and partially formed chemical bonds.

(3) It cannot be isolated out.

• A. (1) and (2) only
• B. (1) and (3) only
• C. (2) and (3) only
• D. (1), (2) and (3)

Which of the options is the energy profile for the single-step reaction shown below?

X → Y + Z　　　ΔH > 0

• A
• B
• C
• D

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NGSS.HS-PS1-4

The energy profile of a two-step reaction is shown in the diagram. Which of the following statements concerning this reaction is INCORRECT?

• A. Species Q is the intermediate.

• B. Step 2 occurs slower than Step 1.
• C. It is endothermic.
• D. Species P is the activated complex of Step 1.

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NGSS.HS-PS1-4

Consider the Maxwell-Boltzmann distribution curve of a gaseous system. Which of the following statements concerning this curve is/are correct?

(1) W represents the kinetic energy possessed by the largest number of particles in the system.

(2) The shaded area under the curve represents the total number of particles in the system.

(3) Eₐ represents the maximum energy possessed by the particles in the system.

• A. (1) only
• B. (2) only
• C. (1) and (3) only
• D. (2) and (3) only

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NGSS.HS-PS3-2

Consider the Maxwell-Boltzmann distribution curve of a gaseous system at temperature x°C. When the temperature is decreased from x°C to y°C, which of the following statements correctly describe the changes of the curve?

(1) The whole area under the curve decreases.

(2) The peak of the curve shifts to the left.

(3) The size of the shaded area decreases.

• A. (1) and (2) only
• B. (1) and (3) only
• C. (2) and (3) only
• D. (1), (2) and (3)

Tags

NGSS.HS-PS1-5

Consider the following reaction:

H₂(g) + I₂(g) ⇌ 2HI(g)

If the rate constant of this reaction at 700 K is 0.170 dm³ mol⁻¹ s⁻¹, what will be the rate constant at 800 K?

(Given: R = 8.31 J K⁻¹ mol⁻¹, Eₐ = 170.7 kJ mol⁻¹)

• A. 17.0 dm³ mol⁻¹ s⁻¹
• B. 668 dm³ mol⁻¹ s⁻¹
• C. 0.170 dm³ mol⁻¹ s⁻¹
• D. 6.68 dm³ mol⁻¹ s⁻¹

Tags

NGSS.HS-PS1-5

Consider the following reaction:

X + Y → Z

The rate constants of the reaction at 25°C and 35°C are k₁s⁻¹ and 2k₁s⁻¹, respectively. What is the activation energy of this reaction?

(Given: R = 8.31 J K⁻¹ mol⁻¹)

• A. 22.1 kJ mol⁻¹
• B. 52.8 kJ mol⁻¹
• C. 251.7 kJ mol⁻¹
• D. 503.4 kJ mol⁻¹

Tags

NGSS.HS-PS1-5