what is?what is?

Effective collision?Effective collision?

Collision theory?Collision theory?

Factors affecting?Factors affecting?

Activation energy?Activation energy?

Energy level diagram?Energy level diagram?

Rate of reactionRate of reaction

AVERAGE RATE OF REACTION

For the whole exp

From X

min to Y min

On the X min (2nd) ( from 2nd to 1st)

For first x

(3) min( from 0 to

3rd )

b) Example from the graph, determine:i) The average rate of reaction for the

whole experiment =

Total volume of gas Total time taken

0

10

20

30

40

50

60

70

80

0 30 60 90 120 150 180 210 240 270 300

Volu

me

of g

as/

cm3

Time/ s

= 46 = 0.20 cm3 s-1

210

b) Example from the graph, determine:i) The average rate of reaction from 3

minute to 1 minute =

Total volume of gas at 3min -1 minTotal time taken at 3min -1min

0

10

20

30

40

50

60

70

80

0 30 60 90 120 150 180 210 240 270 300

Volu

me

of g

as/

cm3

Time/ s

= 44-25 = 0.13 cm3 s-1

180-60

b) Example from the graph, determine:i) The average rate of reaction for on

the 3rd minute=

Total volume of gas at 3min – at 2min Total time taken at 3min – at 2 min

0

10

20

30

40

50

60

70

80

0 30 60 90 120 150 180 210 240 270 300

Volu

me

of g

as/

cm3

Time/ s

= 44-38 = 0.10 cm3 s-1

180-120

b) Example from the graph, determine:i) The average rate of reaction for for

the first 2 minutes=

Total volume of gas at 2min – at 0min Total time taken at 2min – at 0 min

0

10

20

30

40

50

60

70

80

0 30 60 90 120 150 180 210 240 270 300

Volu

me

of g

as/

cm3

Time/ s

= 38-0 = 0.33 cm3 s-1

120-0

INSTANTANEOUS RATE OF REACTION

( rate of reaction at that time) Draw tangent to the

graph

Y

X

Rate = Y/X

b) Example from the graph, determine:i) The rate of reaction at 120 s

Instantaneous rate of reaction= Draw tangent to the graph

0

10

20

30

40

50

60

70

80

0 30 60 90 120 150 180 210 240 270 300

Volu

me

of g

as/

cm3

Time/ s

= 56 – 20 = 0.176 cm3 s-1

222-18

II

IIII

Volume of gas

Time

• Use positive catalyst• Increase temperature •Increase total surface area (TSA)•Increase conc but not the mole of reactant

• decrease temperature •Decrease TSA•Decrease conc but not the mole of reactant

Example: Sketch curve that would be obtained with the changes below:

originalLower temp

Volume of gas

Time

Lower temperature is used

Example: Sketch curve that would be obtained with the changes below:

original

higher temp

Volume of gas

Time

Higher temperature

Example: Sketch curve that would be obtained with the changes below:

originalBigger size

Volume of gas

Time

Bigger size of reactant is used

Example: Sketch curve that would be obtained with the changes below:

original

Smaller size

Volume of gas

Time

Smaller size of reactant

Example: Sketch curve that would be obtained with the changes below:

original

higher temp

Volume of gas

Time

Higher temperature

Example: Sketch curve that would be obtained with the changes below:

original

With catalyst

Volume of gas

Time

Catalyst was added

Changes to the FLAT part of graph

Example:Curve I represents the result of the experiment using excess zinc powder and 50cm3 of 1.0 moldm-3 dilute hydrochloric acid

I

Volume of gas/ cm3

Time/s

Draw curves when condition change:ORIGINAL: 50cm3 of 1.0 moldm-3 dilute hydrochloric acid Change : 50cm3 of 2.0 moldm-3 dilute hydrochloric acid

ori

Volume of gas/ cm3

Time/s

Change

Draw curves when condition change:ORIGINAL: 50cm3 of 1.0 moldm-3 dilute hydrochloric acid Change : 50cm3 of 0.5 moldm-3 dilute hydrochloric acid

ori

Volume of gas/ cm3

Time/s

Change

Draw curves when condition change:ori :50cm3 of 1.0 moldm-3 dilute hydrochloric acid change : 50cm3 of 0.5 moldm-3 dilute hydrochloric acid

ori

Volume of gas/ cm3

Time/s

change

Draw curves when condition change:ORI : 50cm3 of 1.0 moldm-3 dilute hydrochloric acid change : 20cm3 of 1.0 moldm-3 dilute hydrochloric acid

ori

Volume of gas/ cm3

Time/s

change

Draw curves when condition change:ori: 50cm3 of 1.0 moldm-3 dilute hydrochloric acid change: 25cm3 of 2.0 moldm-3 dilute hydrochloric acid

ori

Volume of gas/ cm3

Time/s

change

1. The effect of size of reactant

•Reducing the size of reactant

•increases the Total Surface Area

•increases the frequency of collisions between particles

•Increase the rate of reaction.

•Increase the frequency effective collisions between particles

2. The effect of temperature

•Increase the temperature of solution

•increase the kinetic energy of particles

•increase the frequency of collisions between particles

•Increase the rate of reaction.

•Increase the frequency effective collisions between particles

3. The effect of concentration•Increase the concentration of solution

•increase the number of particles per unit volume

•increase the frequency of collisions between particles

•Increase the rate of reaction.

•Increase the frequency effective collisions between particles

4. The effect of catalyst

•Catalyst provides alternative route

•That has a lower activation energy

•Increase the rate of reaction.

•So more particles have energy equal or greater than activation energy.

•Number of effective collisions increase.

exothermic reaction

Activation energy with catalyst

Activation energy no catalyst

reactant

Write chemical equation ( 9m)•Calcium carbonate and hydrochloric acid ( 2m)

OHCO

CaClHClCaCO

22

23 2

Write chemical equation ( 9m)•Sodium thiosulphate and sulphuric acid( 2m)

OHSOSOSNa

SOHOSNa

2242

42322

Write chemical equation ( 9m)•Decomposition of hydrogen peroxide ( 2m)

2222 22 OOHOH

What is the catalyst used in the decomposition hydrogen peroxide?(1m)

Manganese (IV) oxide

Write ionic equation for Sodium thiosulphate and sulphuric acid (2m)

OHSOSOSNa

SOHOSNa

2242

42322

OHSOS

HOS

22

232 2

End