Question 1

The image shows a laboratory setup used to measure a property of a chemical reaction. Which property is being measured, and what does an increase in the measured value indicate about the reaction progress?

Accepted Answer

The setup measures the electrical conductivity of the solution; an increase indicates that more ions are being produced as the reaction progresses.

Question 2

Which type of chemical reaction would most likely be monitored using the apparatus shown in the image?

Accepted Answer

A reaction that produces ions in solution, such as the hydrolysis of an alkyl halide.

Question 3

Suppose the reaction being monitored is the hydrolysis of 2-methyl-2-chloropropane: $$ (CH_3$)_3CCl(aq) + H_2O(l) \rightarrow (CH_3$)_3COH(aq) + H^+(aq) + Cl^-(aq) . $$What is the main reason the conductivity increases as the reaction proceeds?

Accepted Answer

The concentration of ions increases, allowing the solution to conduct more electricity.

Question 4

If the conductivity meter in the image shows a constant reading over time during a reaction, what does this most likely indicate about the reaction?

Accepted Answer

The reaction has reached completion or equilibrium, and the concentration of ions is no longer changing.

Question 5

Which of the following best describes why a conductivity meter is a suitable method for monitoring the rate of certain chemical reactions?

Accepted Answer

It provides a non-invasive, real-time measurement of ion concentration changes in solution.

Question 6

A student uses the apparatus in the image to monitor a reaction and observes that the conductivity increases rapidly at first, then levels off. What does this suggest about the reaction rate over time?

Accepted Answer

The reaction rate decreases over time as the reactants are consumed.

Question 7

Which of the following reactions would NOT be suitable for monitoring with the apparatus shown in the image?

Accepted Answer

The decomposition of hydrogen peroxide to produce oxygen gas.

Question 8

If the initial conductivity of a solution is 0.005 S/cm and increases to 0.020 S/cm after 10 minutes, what does this change indicate about the chemical reaction occurring in the solution?

Accepted Answer

The reaction is producing more ions as it proceeds.

Question 9

Which of the following best explains why the electrodes in the beaker must not react with the solution during the experiment?

Accepted Answer

To ensure that the measured conductivity reflects only the ions produced by the chemical reaction, not by electrode corrosion.

Question 10

In a reaction monitored by conductivity, the rate of change of conductivity is greatest at the start and decreases over time. Which kinetic principle does this observation illustrate?

Accepted Answer

The reaction rate typically decreases as reactants are consumed and product concentration increases.

Lesson 6.1: Chemical Kinetics: Reaction Rates and Measurement Methods

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