Rate Laws and Reaction Orders

Question 1

3 Methods of Calculating Reaction Order

Answer 1

Initial Rates (results comparion, 1 kept constant), graphical method (integrates rate law) and half life method

Question 2

Initial Rates Method

Answer 2

Finds out differential rate laws. Given initial rates and concentrations to compare relationship between them, to infer partial reaction rates. If more then 1 reactants there will be different runs where 1 varies and others are kept constant

Question 3

Differential Rate Law 0 order reactions

Answer 3

rate = k[reactant conc]^0 = k

Question 4

Differential rate law 1st order reaction

Answer 4

rate = k[reactant conc]^1

Question 5

Differential Rate Law 2nd Order

Answer 5

rate = k [Concentration of reactant]^2

Question 6

Graphical Method Outline

Answer 6

More specific allows for change in conc at specififc time. Use integrated rate laws to try make points a straight line graph. Helps find shelf life, half life and dosage

Question 7

0 order integrated equation (y =mx + c)

Answer 7

[conc of reactant at t] = -kt + [initial reactant conc]

Question 8

1st order integrated equation (y =mx + c)

Answer 8

ln([conc at time t]) = -kt + ln([initial conc])

Question 9

2nd order integrated equation (y = mx + c)

Answer 9

1/([conc at t]) = kt + 1/([initial conc])

Question 10

Graphical Method Slopes

Answer 10

All straight line when correct order is chose. 0 and 1st = negative. 2nd is positive

Question 11

Half Life of 0 order reactions

Answer 11

([initial conc])/2k. Calculate by using integrated equation and having conc at time be 1/2([initial conc])

Question 12

Half life of 1st order reactions

Answer 12

ln2/k

Question 13

Half life of 2nd order reactions

Answer 13

1/((initial conc)(k))

Question 14

How do you work out units of k

Answer 14

integrated rate equation use known units