Kinetics practice 4

In the Maxwell-Boltzmann distribution of kinetic energies in a sample of gas at a particular temperature, the area under the curve represents which of the following?

• the total energies of all the particles in the sample

• the total number of particles in the sample

• the total volume of the gas

• the total mass of the gas

Consider a reaction mixture consisting of 1 mol of gaseous iodine and 1 mol of hydrogen at 200 °C. The experiment is then repeated at 300 °C. Which of the following statements is consistent with comparisons between the Maxwell-Boltzmann distributions for this reaction mixture at these two temperatures?

• The area under the curve is greater for the reaction at 300 °C.

• The area under the curve is smaller for the reaction at 200 °C.

• The peak of the curve flattens and the curve extends towards higher energies for the reaction at 300 °C.

• The peak of the curve becomes sharper and the curve retreats towards lower energies for the reaction at 300 °C.

Tags

NGSS.HS-PS1-5

Which of the following changes will not lead to an increase in the rate of reaction of a gas phase reaction occurring in a high pressure reaction vessel?

• Decreasing the volume of the reaction vessel

• Injecting more reactants into the existing reaction vessel

• Heating the reaction vessel

• Increasing the volume of the reaction vessel

Tags

NGSS.HS-PS1-5

A single, solid piece of calcium carbonate is reacted with excess 1 mol/L hydrochloric acid and the rate of carbon dioxide production is monitored. The experiment is repeated with a similar sized piece of calcium carbonate, but crushed into smaller pieces. Which of the following is inconsistent with the predicted results of the second reaction?

• A larger surface of contact between the calcium carbonate and hydrochloric acid

• An increase in the rate of carbon dioxide production

• An increase in the frequency of successful collisions between the calcium carbonate and hydrochloric acid

• A decrease in the rate of carbon dioxide production

Tags

NGSS.HS-PS1-5

Which of the following is not a required condition for particles to react?

• Particles must collide with each other

• Particles must collide in the correct orientation, so that the reactive parts of each of the two particles make contact

• Particles must collide with kinetic energy greater than or equal to the activation energy (KE ≥ E_a) in order to react

• Particles must collide with kinetic energy less than the activation energy (i.e. KE < E_a) in order to react

A reaction involving a solid reactant in aqueous solution occurs in time t. Which of the following will not increase the rate of reaction?

• Increasing the particle size of the solid

• Doubling the temperature of the solution

• Crushing the solid into smaller pieces

• Increasing the concentration of the solution

Tags

NGSS.HS-PS1-5

The rate of a chemical reaction can be expressed as Δ[R]/Δt, where R is a reactant. Which are the correct units for this expression?

• mol L s^-1

• mol L^-1 s

• mol L^-1 s^-1

• mol L^-1

Tags

NGSS.HS-PS1-5

Which of the following best explains how a catalyst increases the rate of reaction?

• a catalyst provides an alternative pathway of lower activation energy

• a catalyst provides an alternative pathway of higher activation energy

• a catalyst provides an alternative pathway of lower activation energy for the forward reaction only

• a catalyst provides an alternative pathway of lower activation energy for the back reaction only

Tags

NGSS.HS-PS1-4

Which of the following factors determine whether a collision between reactant particles will be a successful collision?

I. particles must collide

II. particles must collide with correct orientation

III. particles must collide with kinetic energy = Ea

• I and II only

• I and III only

• II and III only

• I, II and III

According to collision theory, which of the following factors affect the rate of reaction?

I. Number of particles with KE ≥ E_a

II. The geometry of collisions

III. The frequency of collisions

• I and II only

• I and III only

• II and III only

• I, II and III

Tags

NGSS.HS-PS1-5