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Whatis ?

Effectivecollision?

Collisiontheory?

Factorsaffecting?

Activation

energy?

Energy level

diagram?

Rate of reaction

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What is the rate of a reaction

The rate of the reaction is howquickly the reaction happens.

Fast

reaction

Slowreaction

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Iron rusting - aCHEMICAL

REACTIONwith a slowreaction rate.

Wood burning -a chemical

reaction with afastreaction

rate.

http://en.wikipedia.org/wiki/Chemical_reactionhttp://en.wikipedia.org/wiki/Chemical_reactionhttp://en.wikipedia.org/wiki/Chemical_reactionhttp://en.wikipedia.org/wiki/Chemical_reactionhttp://en.wikipedia.org/wiki/Image:Large_bonfire.jpghttp://en.wikipedia.org/wiki/Image:Rust03102006.JPG

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Whatis ?

Effectivecollision?

Collisiontheory?

Factorsaffecting?

Activation

energy?

Energy level

diagram?

Rate of reaction

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"You cant react if you dont collide."

collision theory

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1. the particles must collideto

react.

3 necessary requirements inorder for a reaction to take place:

2. Collision of particles mustproduceenough energy(to

overcome energy of activation)3. Collisions of particlesmust becorrectly oriented

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Whatis ?

Effectivecollision?

Collisiontheory?

Factorsaffecting?

Activation

energy?

Energy level

diagram?

Rate of reaction

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Prevent Effective collision

Camera to

detect fastmoving traffic

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Effective collision

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Whatis ?

Effectivecollision?

Collisiontheory?

Factorsaffecting?

Activation

energy?

Energy level

diagram?

Rate of reaction

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The energy that must beovercome in order for achemical reaction to occur

Activation energy is theminimum energy necessaryfor a specific chemicalreaction to occur

Activation energy

http://en.wikipedia.org/wiki/Chemical_reactionhttp://en.wikipedia.org/wiki/Chemical_reaction

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The sparks generatedby striking steelagainst a flint provide

the activation energyto initiate combustionin this Bunsen

burner.

Activation energy

http://en.wikipedia.org/wiki/Ferroceriumhttp://en.wikipedia.org/wiki/Bunsen_burnerhttp://en.wikipedia.org/wiki/Bunsen_burnerhttp://en.wikipedia.org/wiki/Bunsen_burnerhttp://en.wikipedia.org/wiki/Bunsen_burnerhttp://en.wikipedia.org/wiki/Ferroceriumhttp://upload.wikimedia.org/wikipedia/commons/1/1b/Incandescence.jpg

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A little

activationenergy is addedwith the aid of a

weed burner...

What is activation energy

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Not enoughkinetic energyfor reactants toleap over

reaction barrier.

A "hot" reaction inprogress showingreactants leapingover the activation

energy barrier

What is activation energy

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Activation energy

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Activation energy

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Only collisions with enough energy react to

form products.The critical amount of energy to make thereaction proceed

What is activation energy

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A + B C + D

reactants products

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What is activation energy

activation

energy

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Whatis ?

Effectivecollision?

Collisiontheory?

Factorsaffecting?

Activation

energy?

Energy level

diagram?

Rate of reaction

Wh t ff t th t f ti ?

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What affects the rate of a reaction?

Size ofreactant

Concentrationof reactants

/pressure

Temperatureof reactionmixture

catalyst

Wh ff h f i ?

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1. The effect of size of reactant

What affects the rate of a reaction?

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1. The effect of size of reactant

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THE EFFECT OF SIZE OF REACTANT

a reaction between magnesium metal and adilute acid like hydrochloric acid.

Increasing the number of collisions persecond increases the rate of reaction.

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Magnesium metal

THE EFFECT OF SIZE OF REACTANT

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Magnesium metal

THE EFFECT OF SIZE OF REACTANT

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1. The effect of size of reactant

Reducing the size of reactant

increases the Total Surface Area

increases the frequency of collisionsbetween particles

Increase the rate of reaction.

Increase the frequency effectivecollisions between particles

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2. Temperature

Increasing temperaturewill increase kinetic energy in the particles

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1. The effect of temperature

Increase the temperature of solution

increase the kinetic energy of particles

increase the frequency of collisionsbetween particles

Increase the rate of reaction.

Increase the frequency effectivecollisions between particles

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3. Concentration and Pressure

Increasing concentration or pressureincreases the number of particles per unit

volume

http://en.wikipedia.org/wiki/Image:Molecular-collisions.jpg

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http://en.wikipedia.org/wiki/Image:Molecular-collisions.jpg

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1. The effect of concentration

Increase the concentration of solution

increase the number of particles perunit volume

increase the frequency of collisionsbetween particles

Increase the rate of reaction.

Increase the frequency effectivecollisions between particles

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- A catalyst will change the rate of areaction.- The catalyst itself does not take part

in the reaction - It is not changed bythe reaction- it is not used up during the reaction.

- A catalyst is usually a transitionmetal, a transition metal oxide

Properties of Catalysts

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4. Catalyst

How does a catalyst work?1) Provides a surface on which

the reaction can take place.2) This increases the number of

collisions between the

particles of the substancesthat are reacting.

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4. Catalyst

Often a catalyst is there to provide a

favourable surface for a reaction totake place

The blackobjectrepresents

thecatalyst

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Examples CATALYSTS

reaction catalyst

Decomposition of

hydrogen peroxide

manganese(IV)

oxide, MnO2Manufacture of ammonia

by the Haber Processiron

Contact Process to makesulphuric acid

vanadium(V)oxide, V2O5

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A catalyst provides an alternative routefor the reaction with a a lower activation

energy.

A ti ti ith t l t

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Activation energy with no catalyst

Activation energy with catalyst

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Activation energy with catalyst

4 The effect of catalyst

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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 orgreater than activation energy.

Number of effective collisions increase.

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Whatis ?

Effectivecollision?

Collisiontheory?

Factorsaffecting?

Activationenergy?

Energy level

diagram?

Rate of reaction

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End of

slides