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1[GCSE Chemistry]1 > Rates of Reaction > Flashcards

Rates of Reaction Flashcards

1
Q

Why is it important to keep fermentation in anaerobic (no oxygen) conditions?

A

Oxygen converts ethanol into ethanoic acid (vinegar) which doesn’t taste nice.

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2
Q

How do you find the rate of reaction on a curved graph?

A

Find the gradient of the tangent.

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3
Q

If magnesium reacts with hydrochloric acid which of the following will speed up the reaction: a. Lower temperature b. Bigger pieces of magnesium c. More concentrated acid d. More dilute acid e. Magnesium powder f. Increasing the temperature

A

a. slower b. slower c. faster d. slower e faster f faster

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4
Q

How do you find the rate of reaction using a gradient?

A

Change in Y

Change in X

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5
Q

Why are catalysts important in industry?

A

+Reactions are quicker +They happen at lower temperatures +So it is cheaper to make product

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6
Q

If magnesium reacts with hydrochloric acid which of the following will speed up the reaction: +a) Lower temperature +b) Bigger pieces of magnesium +c) More concentrated acid +d) More dilute acid +e) Magnesium powder +f) Increasing the temperature

A

+a) slower +b) slower +c) faster +d) slower +e) faster +f) faster

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7
Q

What is an endothermic reaction?

A

A reaction which takes in energy from the surroundings.

Shown by a fall in temperature of the surroundings.

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8
Q

What are precipitates?

A

Insoluble solids which form when two solutions are mixed together.

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9
Q

What is an exothermic reaction?

A

A reaction which give out energy to surroundings.

Shown by a rise in temperature of the surroundings.

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10
Q

Why does increasing pressure of a gas increase the rate of reaction?

A
  • The higher the pressure the faster the reaction.
  • Particles are closer together in a decreased volume
  • So there there would be more frequent collisions.
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11
Q

What rection is this?

A

An exothermic reaction

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12
Q

What does a catalyst do to the activation energy?

A

The catalyst lowers the activation energy. + this means many more collisions are likely to be successful.

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13
Q

Why are catalysts important in the industry?

A

They help substances to react quickly at lower temperatures and pressures than would otherwise be needed. This saves money.

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14
Q

What is an anomalous result?

A

+Does not fit on best line of fit +Higher or lower than expected

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15
Q

Describe how the volume of gas changes

A

Volume of gas increases quickly in first 3 to 4 minutes Then slows down At 8 minutes no more gas made

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16
Q

What is a catalyst?

A

+A substance that speeds up chemical reactions without getting used up in the process or being chemically changed.

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17
Q

What is the rate of reaction?

A

How fast a reaction takes place.

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18
Q

What is MEXO BENDO

A

Making bonds = Exothermic

Breaking bonds = Endothermic

19
Q

Why does increasing concentration of a solution increase the rate of reaction?

A
  • The higher the concentration the faster the reaction.
  • Increasing the concentration means there are more particles of reactant in the same volume
  • So there would be more frequent collisions.
20
Q

What 2 things need to occur for a reaction to take place?

A

+ Must Collide +Must have enough energy to react (for bonds to be made/broken)

21
Q

What are enzymes?

A

Biological catalysts - catalyse chemical reactions in living cells (eg respiration, photosynthesis,protein synthesis)

22
Q

What does it mean if a reaction is slow in terms of activation energy?

A

It means that very few of the collisions occurring have the activation energy required for the reaction to happen. When most of the collisions occur the particles will just bounce off of each other.

23
Q

What does a higher surface area mean?

A

A higher rate.

24
Q

Give 4 factors that affect rate of reaction.

A

+Temperature +Concentration +Surface area +Catalyst

25
Q

What is a catalytic converter?

A
  • A device in a car that helps reduce the production of toxic gases.
  • Increase the rate of reaction of carbon monoxide & nitrogen oxide with exhaust gases with oxygen from the air.
  • Product is CO2 and water - less harmful to the environment.
  • Works best at high temperatures
26
Q

Can you use the same catalyst for any reaction?

A

No it is specific to a certain reaction

27
Q

What is commonly used as a catalyst of the decomposition of hydrogen peroxide?

A

manganese dioxide MnO2

28
Q

How do you increase the surface area of a marble chip?

A

Grind it into smaller pieces

29
Q

What is the equation for the rate of reaction?

A

Rate of reaction = am.nt of reactant used/product formed

time

30
Q

What happens when enzymes are too hot?

A

Enzymes in the yeast denatures (destroyed) and the reaction stops.

31
Q

How does a catalyst decrease the activation energy?

A

It provides an alternative pathway that has a lower activation energy.

32
Q

What reaction is this?

A

An endothermic reaction

33
Q

What is Collision Theory?

A
  • Particles must collide with enough energy in order to react.
  • The more collisions, the higher the rate of reaction.
34
Q

Why does increasing temperature increase the rate of reaction?

A
  • The higher the temperature the faster the reaction.
  • The particles have more energy and move faster so there will be more frequent collisions.
35
Q

In an experiment using a catalyst, how would you test that what you thought is the catalyst, is the catalyst and not a reactant?

A

Filter the contents and weigh the solid. If the mass is the same then it is the catalyst

36
Q

What does a higher concentration mean?

A

A higher rate.

37
Q

Is a line of best fit always a straight line?

A

no can be curved

38
Q

What is the equation for the overall energy change?

A
  • Overall energy change = Energy required to break bonds -Energy released by forming bonds.
    • = Endothermic
    • = Exothermic
39
Q

What is activation energy?

A

The minimum amount of energy that particles need to react when they collide.

40
Q

Describe how the volume of gas changes

A

+Volume of gas increases quickly in first 3 to 4 minutes +Then slows down +At 8 minutes no more gas made

41
Q

What does a higher temperature mean?

A

A higher rate.

42
Q

What effect does increasing the surface area have on the rate of reaction?

A
  • The higher the surface area the faster the reaction.
  • There is a larger area available for the particles to react with.
  • So there would be more frequent collsions.
43
Q

When are reactants used up fastest in a reaction?

A

At the start of the reaction

1[GCSE Chemistry]1 (35 decks)

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