Determining the rate equation

Question 1

How do you determine the order when comparing rate to the change in conc?

Answer 1

• zero order
  
  • change in conc has no affect on rate
• first
  
  • rate directly propotional to conc
• second
  
  • rate is propotional to the square of the conc of the species

Question 2

How is order found from rate-conc graphs?

Answer 2

• plot for certain species
• zero
  
  • horizontal straight line
• first
  
  • sloping straight line thorugh origin
• second
  
  • if not a straight line, the order cannot be found directly
  • try plotting [A]² and if this is a straight line the order is 2
  • must be greater than 1

Question 3

What is the initial rate method?

Answer 3

• series of experiments carried out at constant temp
• different combo of initial conc of reactants, catalysts so on
• comparing initial conc and initial rate allows the order to be found
• practice this

Question 4

What is the rough rule for every 10K rise in temp?

Answer 4

rate of reaction doubles

Question 5

Why must K increase with a temp increase? Why does this happen

Answer 5

• rate = k [A] [B]
• conc remain constant
• rate rises
• k must rise
• increase successful collisons and enough energy to start bond breaking

Question 6

What does a larger value for k mean?

Answer 6

faster rate of reaction