5.1

Question 1

Overall order

Answer 1

Sum of individual orders

Eg. 1st order + 2nd order = 3

Question 2

Units of K (rate constant)

Answer 2

-3 -1

Mol Dm S

Question 3

Concentration-time graphs: 0 order

Answer 3

Straight line slanted downwards

k=ln(2)/half life

Question 4

Concentration-time graphs: 1st order

Answer 4

Normal curved line downwards

k=ln(2)/half life

Question 5

Concentration-time graphs: 2nd order

Answer 5

Steep curved line downwards

k=ln(2)/half life

Question 6

Half life

Answer 6

Help to find the order of a reaction. They are the difference between the 1st half life and 2nd

Question 7

Finding rate constant from graphs using half life

Answer 7

k=ln(2)/half life

Question 8

Rate-concentration graphs: 0 order

Answer 8

Flat straight line

k=rate/concentration (gradient)

Question 9

Rate-concentration graphs: 1st order

Answer 9

Straight line slanted upwards

k=rate/concentration (gradient)

Question 10

Rate-concentration graphs: 2nd order

Answer 10

Curved line upwards

k=rate/concentration (gradient)

Question 11

Relationship between rate and time

Answer 11

Rate is inversely proportional to time

rate=k/t

Question 12

Clock reaction

Answer 12

The time it takes for the colour to change. Then plot the graph 1/t.

Question 13

Determining rate constant from a graph

Answer 13

If it’s first order, k=gradient

Question 14

How does temperature affect the rate constant?

Answer 14

Increase in temperature increases the rate constant (k).This is because more molecules exceed the minimum activation energy so react.

Question 15

Arrhenius equation

Answer 15

-Ea/RT
k=Ae
Used in graphs, with gradient=lnA and y-intercept=-Ea/R

Question 16

Homogeneous equilibrium

Answer 16

All species in the system are in the same state

Question 17

Heterogeneous equilibrium

Answer 17

All species in the system are in different states

Question 18

Kc equation

Answer 18

[Products]
[Reactants]
-For equilibrium reactions
-If heterogeneous, solids and pure liquidws aren’t included in the equation

Question 19

What are the meanings of the Kc/Kp value if it is less than 1?

Answer 19

Equilibrium is to the left

Reactants are favoured

Question 20

What are the meanings of the Kc/Kp value if it is more than 1?

Answer 20

Equilibrium is to the right

Products are favoured

Question 21

What is the affect of a catalyst on equilibrium?

Answer 21

No effect

Question 22

Ka units

Answer 22

mol/dm3

Question 23

What does a large Ka value mean?

Answer 23

Lots of dissociation

Acid is strong

Question 24

What does a small Ka value mean?

Answer 24

If Small amount of dissociation

Acid is weak

Question 25

Ka equation

Answer 25

Ka=[H+][A-]
[HA]
If it’s a weak acid, it will be [H+]^2

Question 26

Kw units

Answer 26

mol2/dm6

Question 27

What can affect Kw?

Answer 27

Temperature

Question 28

Buffers equation

Answer 28

[H+]=Ka[HA]
[A-]

[A-]= the salt
[HA]= the acid

Question 29

How does adding acid affect buffers?

Answer 29

• The salt [A-] decreases because it react with the [H+]
• The acid [HA] increases because it is formed
• The equilibrium shifts to the left

Question 30

How does adding a base affect buffers?

Answer 30

• The salt [A-] increases because [OH-] reacts with [H+] to make H2O, so more acid dissociates
• The acid [HA] decreases
• Equilibrium shifts to the right

Question 31

Indicators

Answer 31

Methyl orange- low pH
Bromothymol blue- medium pH
Phenolphthalein- high pH

Question 32

Indicator for both strong acid and base

Answer 32

Any indicator

Question 33

Indicator for strong acid-weak base

Answer 33

methyl orange

Question 34

Indicator for weak acid-strong base

Answer 34

phenolphthalein

Question 35

Indicator for both weak acid and base

Answer 35

No indicator