different chemical reactions varies hugely. Some reactions are very
fast and others are very slow.What is the rate of these reactions?
The speed of a reaction is called the rate of the reaction.
rusting
baking
explosion
slow
fast
very fast
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Презентация на тему Rates of reaction
Содержание
- 3. What does rate of reaction mean?The speed
- 4. Rates of reactionWhy are some reactions faster than others?
- 5. Reactions, particles and collisionsReactions take place when
- 6. Changing the rate of reactionsincreased temperatureincreased concentration
- 7. Slower and slower!Reactions do not proceed at
- 8. Graphing rates of reaction
- 9. Reactant–product mix
- 10. How can rate of reaction be measured?Measuring
- 11. Setting up rate experimentsWhat equipment is needed to investigate the rate of hydrogen production?
- 12. hydrogen produced (cm3)time (seconds)10203040501020304050607000xyCalculating rate of reaction
- 13. The reactant/product mix
- 14. Collisions and reactions: summary
- 16. Temperature and collisionsHow does temperature affect the rate of particle collision?
- 17. Effect of temperature on rateThe higher the
- 18. Temperature and particle collisions
- 19. Temperature and batteriesWhy are batteries more likely
- 20. How does temperature affect rate?The reaction between
- 21. The effect of temperature on rate
- 23. Effect of concentration on rate of reactionThe
- 24. Concentration and particle collisions
- 25. The effect of concentration on rate
- 26. Effect of pressure on rate of reactionThe
- 28. Effect of surface area on rate of
- 29. Surface area and particle collisions
- 30. Reaction between a carbonate and acidMarble chips
- 31. The effect of surface area on rate
- 32. What are catalysts?Catalysts are substances that change
- 33. Everyday catalystsNickel is a catalyst in the
- 34. Catalysts in industryCatalysts are also essential for
- 36. Glossaryactivation energy – The amount of energy
- 37. Anagrams
- 38. Rates of reaction: summary
- 39. Скачать презентацию
- 40. Похожие презентации
What does rate of reaction mean?The speed of different chemical reactions varies hugely. Some reactions are very fast and others are very slow.What is the rate of these reactions?The speed of a reaction is called the
Слайд 3
What does rate of reaction mean?
The speed of
Слайд 5
Reactions, particles and collisions
Reactions take place when particles
collide with a certain amount of energy.
The minimum amount
of energy needed for the particles to react is called the activation energy, and is different for each reaction.The rate of a reaction depends on two things:
the frequency of collisions between particles
the energy with which particles collide.
If particles collide with less energy than the activation energy, they will not react. The particles will just bounce off each other.
Слайд 6
Changing the rate of reactions
increased temperature
increased concentration of
dissolved reactants, and increased pressure of gaseous reactants
increased surface
area of solid reactantsuse of a catalyst.
Anything that increases the number of successful collisions between reactant particles will speed up a reaction.
What factors affect the rate of reactions?
Слайд 7
Slower and slower!
Reactions do not proceed at a
steady rate. They start off at a certain speed,
then get slower and slower until they stop.As the reaction progresses, the concentration of reactants decreases.
This reduces the frequency of collisions between particles and so the reaction slows down.
Слайд 10
How can rate of reaction be measured?
Measuring the
rate of a reaction means measuring the change in
the amount of a reactant or the amount of a product.What can be measured to calculate the rate of reaction between magnesium and hydrochloric acid?
The amount of hydrochloric acid used up (cm3/min).
The amount of magnesium chloride produced (g/min).
The amount of hydrogen product (cm3/min).
Слайд 11
Setting up rate experiments
What equipment is needed to
investigate the rate of hydrogen production?
Слайд 12
hydrogen produced (cm3)
time (seconds)
10
20
30
40
50
10
20
30
40
50
60
70
0
0
x
y
Calculating rate of reaction from
graphs
The gradient of the graph is equal to the
initial rate of reaction at that timeHow can the rate of reaction be calculated from a graph?
Слайд 17
Effect of temperature on rate
The higher the temperature,
the faster the rate of a reaction. In many
reactions, a rise in temperature of 10 °C causes the rate of reaction to approximately double.Why does increased temperature increase the rate of reaction?
At a higher temperature, particles have more energy. This means they move faster and are more likely to collide with other particles.
When the particles collide, they do so with more energy, and so the number of successful collisions increases.
Слайд 19
Temperature and batteries
Why are batteries more likely to
rundown more quickly in cold weather?
At low temperatures
the reaction that generates the electric current proceeds more slowly than at higher temperatures.This means batteries are less likely to deliver enough current to meet demand.
Слайд 20
How does temperature affect rate?
The reaction between sodium
thiosulfate and hydrochloric acid produces sulfur.
Sulfur is solid and
so it turns the solution cloudy.How can this fact be used to measure the effect of temperature on rate of reaction?
Слайд 23
Effect of concentration on rate of reaction
The higher
the concentration of a dissolved reactant, the faster the
rate of a reaction.Why does increased concentration increase the rate of reaction?
At a higher concentration, there are more particles in the same amount of space. This means that the particles are more likely to collide and therefore more likely to react.
Слайд 26
Effect of pressure on rate of reaction
The gas
particles become closer together, increasing the frequency of collisions.
This means that the particles are more likely to react.Why does increasing the pressure of gaseous reactants increase the rate of reaction?
As the pressure increases, the space in which the gas particles are moving becomes smaller.
Слайд 28
Effect of surface area on rate of reaction
Any
reaction involving a solid can only take place at
the surface of the solid.If the solid is split into several pieces, the surface area increases. What effect will this have on rate of reaction?
The smaller the pieces, the larger the surface area. This means more collisions and a greater chance of reaction.
This means that there is an increased area for the reactant particles to collide with.
Слайд 30
Reaction between a carbonate and acid
Marble chips are
made of calcium carbonate. They react with hydrochloric acid
to produce carbon dioxide.The effect of increasing surface area on the rate of reaction can be measured by comparing how quickly the mass of the reactants decreases using marble chips of different sizes.
Слайд 32
What are catalysts?
Catalysts are substances that change the
rate of a reaction without being used up in
the reaction.Catalysts never produce more product – they just produce the same amount more quickly.
Different catalysts work in different ways, but most lower the reaction’s activation energy (Ea).
Слайд 33
Everyday catalysts
Nickel is a catalyst in the production
of margarine (hydrogenation of vegetable oils).
Many catalysts are transition
metals or their compounds. For example: Platinum is a catalyst in the catalytic converters of car exhausts. It catalyzes the conversion of carbon monoxide and nitrogen oxide into the less polluting carbon dioxide and nitrogen.
Iron is a catalyst in the production of ammonia from nitrogen and hydrogen (the Haber process).
Слайд 34
Catalysts in industry
Catalysts are also essential for living
cells. Biological catalysts are special types of protein called
enzymes.Why are catalysts so important for industry?
Products can be made more quickly, saving time and money.
Catalysts reduce the need for high temperatures, saving fuel and reducing pollution.
Слайд 36
Glossary
activation energy – The amount of energy needed
to start a reaction.
catalyst – A substance that increases
the rate of a chemical reaction without being used up.concentration – The number of molecules of a substance in a given volume.
enzyme – A biological catalyst.
rate of reaction – The change in the concentration over a certain period of time.
