Rates of reaction

Question 1

What is the rate of reaction

Answer 1

the rate of formation of a product, or disappearance of a reactant, per unit time. One can measure mass/volume/concentration changes etc.

Question 2

What does the rate of reaction depend on?

Answer 2

Concentration/pressure
Tempurature
Surface area
Catalysts
Light

Question 3

Collision theory

Answer 3

Particles must collide to create a reaction

But not all collisions create reactions

Therefore successful collisions must take place to make reactions

Question 4

What increases particle collision

Answer 4

Pressure - An increase in pressure makes an increase in number of particles per unit volume

Increasing surface area will also increases collisions

Tempurature - An increase in tempurature gives more energy to the particles making them move more(kinetic energy) which means more collisions

Question 5

Essentials to know about catalysts

Answer 5

Catalyst - a substance which speeds up the rate of a chemical reaction, but can be recovered unchanged in mass or composition at the end of the reaction
one individual particle of catalyst can be used again and again
different reactions need different catalysts
catalysts work by providing an alternative reaction pathway of lower activation energy so more collisions occur at an energy which exceeds the [new] activation energy

Question 6

Examples of catalysts

Answer 6

Biological detergent - breaks down fats and proteins

Question 7

What is an exothermic reaction

Answer 7

It is a reaction where heat energy is given out to the surroundings as the total energy of the bonds broken is less than the bonds formed

Question 8

What is an endothermic reaction

Answer 8

It is a reaction where heat is taken in from its surroundings.