The rate and extent of chemical change Flashcards

1
Q

If a reversible reaction is endothermic in forward direction, what will it be in the reverse direction?

A

Exothermic

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2
Q

Which reaction shows the fastest rate of reaction? A, B or C?

A

A

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3
Q

For a reversible reaction at equilibrium, what effect will decreasing temperature have on the exothermic reaction

A

The amount of product increases

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4
Q

What effect will increasing the concentration of a reactant have on a reversible reaction?

A
  • More products will be formed
  • Until equilibrium is reached again
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5
Q

What theory states that chemical reactions only occur when reacting particles collide with enough energy?

A

Collision Theory

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6
Q

Calculate the mean rate of reaction for a reaction producing 50 cm3 of gas in 5 s (Give the correct units).

A

50 cm3 / 5 s = 10 cm3/s

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7
Q

What is a catalyst?

A

A substance that increases the rate of a reaction without being used up in the reaction by providing an alternative pathway with a lower activation energy.

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8
Q

What is Le Chatelier’s Principle?

A

The idea that if you change the conditions(such as temperature and pressure) of a reversible reaction at equilibrium, the system will try to counteract the change.

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9
Q

Calculate the mean rate of reaction for a reaction where 5 g of calcium carbonate completely reacts in 10 s (Give the correct units).

A

5 g / 10 s = 0.5 g/s

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10
Q

For a reversible reaction at equilibrium, what effect will increasing temperature have on the endothermic reaction

A

The amount of product increases

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11
Q

Explain how pressure affects the rate of reaction.

A

Increasing the pressure……increases the frequency of collisions……and so increases the rate of reaction.

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12
Q

Explain how concentration affects the rate of reaction.

A

Increasing the concentration……increases the frequency of collisions……and so increases the rate of reaction.

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13
Q

What is the name for the straight line drawn next to the curve at the point indicated by the arrow?

A

Tangent

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14
Q

How would you add a line to show the effect of a catalyst on the reaction profile below?

A
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15
Q

What two equations can be used to measure the rate of a reaction?

A
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16
Q

For a gaseous reaction at equilibrium, what would be the effect of increasing pressure

A

Equilibrium position will shift towards the side with the smaller number of molecules

17
Q

What does ‘equilibrium’ mean?

A

In a reversible reaction, the forward and reverse reactions occur at exactly the same rate.

18
Q

For a reversible reaction at equilibrium, what effect will increasing temperature have on the exothermic reaction

A

The amount of product decreases

19
Q

Explain how temperature affects the rate of reaction.

A

Increasing temperature……Increases the frequency of collisions……The collisions are more energetic.

20
Q

How does a catalyst work?

A

Catalysts increase the rate of reaction……by providing an alternative pathway for the reaction……with a lower activation energy.

21
Q

What is the name for the minimum amount of energy needed for a reaction to happen?

A

Activation Energy

22
Q

List the 5 things that can affect the rate of a reaction.

A
  1. Concentration (of solutions)
  2. Pressure (of gases)
  3. Surface area (of solids)
  4. Temperature
  5. Catalysts
23
Q

For a gaseous reaction at equilibrium, what would be the effect of decreasing pressure

A

Equilibrium position will shift towards the side with the larger number of molecules

24
Q

Calculate the rate of reaction when 2 moles of magnesium oxide reacts in 4 seconds.

A

2 moles / 4 s = 0.5 mol/s

25
How would you calculate the rate of the reaction at the point indicated by the arrow?
* Draw a tangent at that point * Calculate the gradient of the tangent
26
Explain how surface area affects the rate of reaction.
Increasing the surface area ......increases the frequency of collisions......and so increases the rate of reaction.
27
For a reversible reaction at equilibrium, what effect will decreasing temperature have on the endothermic reaction
The amount of product decreases
28
What is the symbol for a reversible reaction?