Rate of reactions

Question 1

Rate of reaction

Answer 1

The concentration cahnge of a reactant and product ina given time

Question 2

Order

Answer 2

The power to which the concentration of a reactant is raised In a rate equation

Rate of reaction is proportional to teh conc of a particular raised to a power

rate proportional = (a)^n

Question 3

Overall order

Answer 3

The sum of the individual orders of reactant in the rate equation

Question 4

Equations for rate =

Answer 4

quantity reacted or produced/ time

change in conc/time

Question 5

Rate units

Answer 5

mol dm-3 / s

written as moldm-3s-1

Question 6

How can concentration be shown ?

Answer 6

Using SQUARE BRACKETS

Question 7

Zero order concentration

Answer 7

Conc of a reactant has NO effect on the rate

Rate directly proportional to (A)^0

Any number raised to the power of zero is 1
Concentration does NOT influence rate

Question 8

FIRST ORDER concentration

Answer 8

When the rate depends on its concentration raised to power of 1

Rate directly proportional to (a)^1

If the conc is doubled, reaction rate increases by 2
if tripled, increases by 3

Question 9

SECOND ORDER concentration

Answer 9

When the rate depends on its conc raised to the power of 2

Rate directly prop to (A)^2

If the conc of of A is doubled, reaction rate increases by 4

If conc of A is tripled, reaction rate increases by 9

Question 10

The rate equation?

Answer 10

Rate= k (A)a (B)b

Question 11

K?

Answer 11

the rate constant that links the rate of reaction with teh conc of reactants raised to the power of their orders

Question 12

How to find overall order from rate reaction ? what does it tell you

Answer 12

a+b( powers)

Tells you how many molecules are involved in the rate determining step

Question 13

What is the rate determining step?

Answer 13

The slowest step in a multistep reaction

Fastest speed the reaction can go at 
THe order tells you how many molecules of it are involved in rds 
zero - doesnt take part 
first - 1 molecule taes part 
second- 2 molecules take part

Question 14

CONC- time graphs

zero, first and second order

Answer 14

ZERO-Steep downwards gradient
FIRST- Downwards sloping curve
SECOND_- DOwnwards sloping curve steeper

Question 15

First order conc time graphs

Answer 15

Half life can be used to ensure its first order

Exponential decay

Should be the same amount of time, when you have the conc and halve again

Question 16

Determination of k for first order reactions

Answer 16

-Calculating the rate constant from the rate
Drawing a tangent to the curve at a particular conc
K=rate/conc ( rate= x/y)

• Calculating the rate constant from half life
  k= ln2/t1/2 (t1/2 - the time for each half life)

Question 17

rate conc graphs for ZERO

Answer 17

rate= k(A)^0 so rate=k

Straight horizontal line

Question 18

Rate conc graphs for FIRST order

Answer 18

Rate= k(A)^1 so rate=k(a)

Straight line, positive

Question 19

Second order rate conc graphs

Answer 19

A curve( going upwards)

Plot a second graph of the rate against conc squared
Straight line through the origin

The gradient is equal to teh rate constant k