chapter 18

Question 1

what is a colorimeter

Answer 1

• a quantitive technique where the intensity of a colour is is followed

Question 2

what happens to a coloured reactant in the reaction

Answer 2

• the intensity of the colour will change

Question 3

what happens in a colorimeter

Answer 3

• the wavelength of the light passing through is controlled using a filter
• the amount of light absorbed is measured
• the absorbance is proportional to the concentration

Question 4

how do you construct a calibration curve

Answer 4

• prepare standard solutions of known concentration
• select a suitable filter
• zero the colorimeter with distilled water
• measure the absorbance reading of the standard solutions of iodine
• plot a calibration curve of absorbance against concentration

Question 5

what is a calibration curve used for

Answer 5

• its a way of converting an absorbance reading into a concentration

Question 6

What is the reaction mechanism?

Answer 6

The series of steps that make up an overall reaction.

Question 7

What is the rate determining step?

Answer 7

The slowest step in the reaction.

Question 8

What does a rate equation include?

Answer 8

The reacting species in the rate determining step.

Question 9

What does the order of reactants in the rate equation tell us?

Answer 9

Their stoichiometry.

Question 10

How can rate constants be determined experimentally?

Answer 10

Carry out the same experiment at different temperatures.
Calculate K at different temperatures using the results.

Question 11

What does Arrhenius’ equation show?

Answer 11

The exponential relationship between the rate constant and the temperature.