Chapter Five : Rates of Reactions

Question 1

Collision Theory

Answer 1

States that a chemical reaction has particles that are moving in random motion and the rate of successful collisions give the rate of reaction

Question 2

Collision Theory reaction requirements

Answer 2

Reactants must;
Collide
Have correct orientation to break bonds
Have sufficient energy for reactants to occur

Question 3

How are reaction rates observed

Answer 3

Volume of gas evolved
Mass of a solid formed
Decrease in mass
Intensity of colour
Formation of a precipitate
pH
Temperature

Question 4

Maxwell-Boltzmann distribution curves

Answer 4

Statistical range of energies present in particles of a gas sample
Number of particles with a particular energy graphed against the energy
Shows the velocities of particles
Highest part represents most probable velocity

Question 5

Factors that affect rate of reaction

Answer 5

Concentration
Pressure
Temp
Catalysts
Surface Area

Question 6

Effect of concentration on rate of reaction

Answer 6

When concentration is increased there are more particles to bounce off each other increasing rate of successful collisions

Question 7

Effect of pressure on rate of reaction

Answer 7

When pressure is increased the particles increase their rate of successful collisions

Question 8

Effect of temp on rate of reaction

Answer 8

Increases the amount of particles with high energy, more particles have enough energy to break bonds
Also increases frequecy of collisions due to faster moving particles

Question 9

Catalyst effect on rate of reaction

Answer 9

Provides an alternative reaction pathway with a lower activation energy
It allows particles with less energy to break the bonds of reactants

Question 10

Surface area effect on rate of reaction

Answer 10

Increasing surface area means that more reactant particles can collide with one another and therefore there are more successful collisions