INTRO TO REACTION KINETICS

Question 1

Define: Rate of reaction

Answer 1

a measure of speed at which the concentration of products increases (or the concentration of reactants decreases)

Question 2

Calc rate of reaction

Answer 2

(difference in [P]) / t OR (- difference [R]) / t

Question 3

Techniques for determining a rate experimentally

Change in volume of gas produced/increase in gas pressure

Answer 3

• measure change in vol. of gas at regular time intervals

- use a gas syringe (or inverted burette) to observe/record volume directly

Question 4

Techniques for determining a rate experimentally

Change in mass

Answer 4

• allows for continuous readings so that mass against time can be plotted
• works well for heavier gases

Question 5

Techniques for determining a rate experimentally

Change in concentration measured using titration

Answer 5

• measure [react.] or [prod.] at certain time intervals by titrating against a “standard”
• since this technique involves a chemical reaction, it can’t be done continuously, takes “freeze” frames of the reaction instead

Question 6

Techniques for determining a rate experimentally

Change in colour

Answer 6

• allows for continuous readings

- plot absorbance/transmittance against time

Question 7

Techniques for determining a rate experimentally

Change in concentration measured using conductivity

Answer 7

• the decrease in [ions] will correspond to a decrease in electrical conductivity

Question 8

Techniques for determining a rate experimentally

“Clock methods”

Answer 8

• sometimes when a reaction is complete, an observable change occurs
• this only gives an average rate over a certain time interval