6.1 Collision theory and rate of reaction

Question 1

Define rate of reaction

Answer 1

Rate ofreaction - increase in concentration of products per unit time

or

decrease in concentration of reactants per unit time

UNITS: mol dm^-3s^-1

Question 2

Why Ea is needed

Answer 2

To overcome the repulsion between particles - enter the transition state from which products can form

Question 3

How to calculate the rate of reaction at a particular point form the graph?

Answer 3

Reaction rate is not constant - different at different points

Find the value of tangent at that point

Question 4

Common methods to recors reaction rates

Answer 4

• gas syringe/water displacement
• mass detection: production of gas
• spectroscopy/colorimetry: if one of reactants/products is coloured or indicator used
• change in concentration via titration
• change in concentration measured by conductivity: conc of ions changes

Question 5

State the collision theory

Answer 5

Chemicals can only react if they collide in the correct geomerty and have the minimal energy for the reaction to occur - activation E

Question 6

Explain the Maxwell-Boltzmann distribution curve

Answer 6

How many particles from all have enough E to react - if have - overcome the repulsion - enter the transition state from which products can form

Question 7

What are the factors which affect the rate of reactions

Answer 7

• temperature
• concentration of reactants
• particle size
• catalyst
• pressure (for gases only)

Question 8

Catalyst effect on reaction energy

Answer 8

Question 9

Catalyst effect on Maxwell - Boltzmann distribution curve

Answer 9

Question 10

Temperature effect on Maxwell - Boltzamann distribution curve

Answer 10