Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

CHEMISTRY as - ocr a > 10- Reaction Rates And Equilibrium > Flashcards

10- Reaction Rates And Equilibrium Flashcards

You may prefer our related Brainscape-certified flashcards:
Periodic Table flashcards Chemistry 101 flashcards AP® Chemistry flashcards Organic Chemistry 101 flashcards
1
Q

Rate of a chemical reaction definition

A

Measures how fast the reactants are being used up or products are being formed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Rate of reaction (concentration) definition

A

The change in concentration of a reactant or product in a given time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What conditions are required for a reaction to take place

A

The particles collide with the correct orientation

The particles must have sufficient energy to overcome the activation energy barrier of the reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Activation energy definition

A

The minimum amount of kinetic energy required for a reaction to occur

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What 5 things can alter the rate of a chemical equation

A

Increasing temperature

Increasing SA

Increasing pressure

Increasing concentration

Use of a catalyst

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How does temperature affect the rate of reaction

A

Temperature increases the rate of reaction by…

Increases KE of particles

Greater proportion of the particles will have at least the activation energy - more effective collisions

Causes them to move faster and collide more frequently increasing the chances of effective collisions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How does concentration / pressure alter rate of a chemical reaction

A

Increasing concentration/pressure increases the rate of reaction

It increases the number of particles in the same volume

Particles are closer together

Collide more frequently

More likely to be more effective collisions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How do catalysts affect rate of reaction

A

Catalysts increase rate of reaction

They lower the activation energy

By providing an alternative reaction pathway

A greater proportion of particles will have enough energy to react

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the different types of ways to measure reaction rates

A

How quickly the reactants are used up = removal of reactant

How quickly the products are formed = formation of a product

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

List of ways of measure rate of reaction practicals

Record then graph …

A
  • colour changes in solutions
  • mass change
  • volume of gas produced
  • pressure changes in gasses
  • changes in conductivity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Monitoring the loss of mass of reactants using a balance practical

A

1) add reactants to conical flask
2) record initial mass
3) add catalyst
4) record mass at regular intervals until no change

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Monitoring volume of gas produced at regular time intervals using gas collection

A

1) add reactants to conical flask and replace bung
2) record the initial volume
3) add catalyst
4) measure volume at regular interval changes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Catalyst definition

A

A catalyst increases the rate of reaction by providing an alternative reaction pathway with a lower activation energy. The catalyst is chemically unchanged by the end of the reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Heterogeneous catalyst definition

A

A reaction in which the catalyst has a different physical state from the reactants

Reactants = gases
Catalyst = solid
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How does a heterogenous catalyst operate

A

Reaction takes place on surface of the catalyst
Reactant is absorbed onto surface (forms weak bonds)
Product leaves through desorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Homogenous catalyst definition

A

A reaction in which the catalyst and the reactants are in the same physical state

Aqueous

17
Q

How do homogeneous catalysts operate

A

Catalysts react with the reactants to form an intermediate species

Which breaks down to give products and regenerates the catalyst

18
Q

What is the economic importance of catalysts

A
  • Catalysts lower the production costs
    By producing more products in shorter time
    And reducing the energy required by using lower temperatures
  • change the properties of a product to make it more useful
19
Q

Why are catalysts good for environmental sustainability

A

-Preserves energy

-Reduces waste
By producing fewer pollutants as higher at economy
Convert harmful pollutants into safer ones

20
Q

What is Boltzmann distribution

A

The spread of molecular energies in gases

21
Q

What does Boltzmann distribution curve show

A

Shows the different kinetic energies a number of molecules have in a substance

22
Q

How does increasing temperature affect a Boltzmann distribution curve

A

Temperature increases the average energy of the molecules - molecules have higher energy

The graph will stretch

  • the peak will be lower
  • and further along the x axis
  • area is the same
23
Q

How do catalysts affect the Boltzmann distribution curve

A

Activation energy is lower on graph

More particles in effective collisions area

24
Q

Dynamic equilibrium definition

A

The equilibrium that exists in a closed system when the rate of the froward reaction is equal to the rate of the reverse reaction and concentration do not change

25
Q

Reverse reaction definition

A

A reaction that takes place in both the forward and reverse direction

26
Q

Homogenous equilibrium definition

A

Equilibrium in which all of the reactants and products are present in a single solution (in the same phase)

27
Q

What 3 things can change the position of equilibrium

A

Concentration
Pressure
Temperature

28
Q

Le chapeliers principle

When a system in dynamic equilibrium is subjected to a external change, the system readjusts itself to…

A

minimise the effect of the change and restore equilibrium

29
Q

Concentration rules
Le chateliers principle

When concentration of reactants increases

A

Shift to the side to get rid of that reactant

Minimise the extra reactant

30
Q

When pressure increases

Chateliers principle

A

Shifts to the side with the fewest molecules

To minimise the increase in pressure

31
Q

When temperature increases

Le chateliers principle

A

Shifts to endothermic direction
That absorbs this heat
To minimise the increases in temp

32
Q

Catalyst effect on position of equilibrium

A

Has no effect
Just speeds up the rate of forwards and reverse reactions equally
Equilibrium reached faster

33
Q

Why compromise temp in industries

A

Although low temp produces higher yield

The rate of reaction is too slow

So compromise between yield and faster reaction

34
Q

Why compromise pressure

A

High pressure produces higher yield and rate of reaction

But is expensive and unsafe

Compromise between yield and expense

35
Q

Equilibrium constant

A

Gives you an idea of how far to the left or right the equilibrium is

36
Q

Kc = 1

Equilibrium =

A

Halfway between reactants and products

37
Q

Kc > 1

Equilibrium =

A

Towards the products

Further to the right

38
Q

Kc < 1

A

Towards the reactants

Further to the left

CHEMISTRY as - ocr a (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions