Chemical Reactions: Rate of Reactions Flashcards
How can we find the rate of reaction? (2)
Measure how quickly reactants are used up
Measure how quickly products are formed
What is the relationship between surface area and reaction rate? (2)
Rate of reaction increases when surface area is increased
Greater the surface area, more particles available to react, particles collide often
What is the danger of explosive reactions? (5)
Industrial processes cause fine powders to get into air
Powders are highly combustible
Burn readily in air due to high surface area
E.g. flour in flour mills/ wood dust in saw mills
Methane in coal mines can form explosive mixture with air
What is the relationship between catalysts and reaction rate? (3)
Catalyst can be used over and over again, not used up
Catalysts provides a more ideal environment as it lowers the activation energy
Often in pellets or wire gauzes - large surface for reactions to occur on
What is the relationship between concentration and reaction rate? (4)
increasing concentration of reactants increases rate of reaction
Concentrated solutions have more particles of solute per unit volume than dilute
Higher concentration → more frequent collision of particles
Rate of reaction depends on number of successful collisions per second, more collisions → faster
What is the first way temperature can affect reaction rate? (3)
Higher temperature → greater rate of reaction
Temperature increase, particles gain energy, move faster and collide more often
Increased rate
What is activation energy?
minimum amount of energy particles need in order to react
What is the second way temperature can affect reaction rate?
Temperature higher → more particles have minimum activation energy when colliding, higher chance of successful reactions
What are photochemical reactions?
chemical reactions started by ultraviolet or visible light.
