Reactivity 3

Question 1

In aqueous solutions, hydrogen ions combine with water molecules to form what?

Answer 1

Hydronium ions - H3O+

Question 2

Brønsted-Lowry theory states that an acid is? (In terms of protons)

Answer 2

A substance that can donate a proton

Question 3

Brønsted-Lowry theory states that a base is what? (In terms of protons)

Answer 3

A substance that can accept a proton

Question 4

What is a Brønsted-Lowry acid?

Answer 4

A proton donor

Question 5

What is a Brønsted-Lowry base?

Answer 5

A proton acceptor

Question 6

What is a conjugate base?

Answer 6

When a Brønsted-Lowry acid loses a a proton

Question 7

What differs a conjugate acid-base pair?

Answer 7

One H+ ion (a proton.)

Question 8

What two ions is pure water dissociated into?

Answer 8

Hydrogen and hydroxide ions combine

Question 9

Are strong acids completely dissociated in aqueous solutions?

Answer 9

Yes

Question 10

What is the concentration of the hydrogen ions in solution of monoprotic acids equal to? Why?

Answer 10

The concentration of the acid, due to full dissociation and mole ratio.

Question 11

What is the concentration of hydrogen ions in solution of diprotic acids equal to?

Answer 11

Twice the concentration of the acid

Question 12

What are the two ways of determining pH practically?

Answer 12

Universal indicator and pH meter

Question 13

Do strong acids dissociate into their ions in aqueous solutions?

Answer 13

Yes, completely

Question 14

Do weak acids and bases dissociate into their ions in aqueous solutions?

Answer 14

Yes, but only partially

Question 15

Undissociated weak ions are in what with their own ions?

Answer 15

Equilibrium

Question 16

For Ka, the smaller the value, the ? the acid?

Answer 16

Weaker

Question 17

For pKa, the higher the value, the lower the Ka value, the ? the acid?

Answer 17

Weaker

Question 18

For the pKb value, the higher the value, the lower the Kb value, and the ? the base?

Answer 18

Weaker

Question 19

What is Ka?

Answer 19

The acid dissociation constanr

Question 20

Regarding electrical conductivity, strong acids and bases have low/high electrical conductivity?

Answer 20

High

Question 21

The pH of a strong acid solution will be lower than the pH of a weak acid solution with the same concentration. This is the same for bases. Why?

Answer 21

The hydrogen ion concentration

Question 22

The rate of reaction in weak acids is lower than that in strong acids, why?

Answer 22

Lower concentration of hydrogen ions

Question 23

Do strong acids have weak or strong conjugate bases?

Answer 23

Weak

Question 24

Why do strong acids have weak conjugate bases?

Answer 24

Because the conjugate base has very little tendency to gain a proton from the undissociated acid.

Question 25

Do weak acids have strong or weak conjugate bases?

Answer 25

Strong

Question 26

Why do weak acids have strong conjugate bases?

Answer 26

The conjugate base is very accepting of a proton

Question 27

Neutralisation reactions are exo or endothermic?

Answer 27

Exothermic

Question 28

Methyl orange goes red and yellow. But in what?

Answer 28

Acid and alkali

Question 29

Bromothymol blue goes blue and yellow. But in what?

Answer 29

Alkali and acid

Question 30

Phenolphthalein goes pink and colourless. But in what?

Answer 30

Alkali and acid

Question 31

Oxidation is defined as (in terms of oxidation states)

Answer 31

The increase in oxidation state

Question 32

Reduction is defined as (in terms of oxidation states)

Answer 32

The decrease in oxidation state

Question 33

Disproportionation definition

Answer 33

Where an element is oxidised and reduced simultaneously

Question 34

In terms of transfer of electrons, define oxidation and reduction

Answer 34

Removal of electrons - oxidation Addition of electrons - reduction

Question 35

Oxidising agents are easily ?

Answer 35

Reduced

Question 36

Reducing agents are easily ?

Answer 36

Oxidised

Question 37

Acidified potassium permanganate colour change

Answer 37

Purple - pale pink

Question 38

Sodium thiosulfate colour change

Answer 38

Brown/yellow - blue

Question 39

Voltaic cells enable the electrons transferred to produce what type of energy?

Answer 39

Electrical

Question 40

Batteries convert chemical energy to what other type of energy?

Answer 40

Electrical

Question 41

Primary cell properties

Answer 41

Not reusable

Question 42

Secondary cell example, and properties

Answer 42

Lead acid, lithium ion, these can be recharged

Question 43

Fuel cell properties

Answer 43

They are infinite

Question 44

Lead acid battery three main components

Answer 44

Pb, PbO2, and H2SO4

Question 45

What two elements are evolved during recharging of a lead-acid battery?

Answer 45

Hydrogen and oxygen

Question 46

Disadvantages of lead acid battery

Answer 46

Heavy and polluting

Question 47

Electrolytic cells - energy is provided externally or internally? Spontaneous or nonspontaneous?

Answer 47

Externally as electricity, nonspontaneous

Question 48

In electrolytic cells, cations move where, where what occurs? And anions move where, where what occurs?

Answer 48

Cations move to the cathode, where reduction occurs, and anions move towards the anode, where oxidation occurs

Question 49

Oxidation always happens at the anode. In voltaic cells vs electrolytic cells, what is the anode? (Positive/negative)

Answer 49

Voltaic - negative, electrolytic - positive

Question 50

What oxidising agents are used to oxidise primary and secondary alcohols?

Answer 50

Acidified potassium dichromate and acidified potassium manganate

Question 51

How to oxidise tertiary alcohols so they still retain their carbon chains?

Answer 51

Burn them

Question 52

Primary alcohols are oxidised to?

Answer 52

Aldehyde and carboxylic acid

Question 53

When acidified potassium dichromate is used, what is the colour change?

Answer 53

Orange-green

Question 54

When acidified potassium manganate is used, what is the colour change?

Answer 54

Purple-very pale pink

Question 55

Secondary alcohols are oxidised to what?

Answer 55

Ketones

Question 56

What are the two common reducing agents?

Answer 56

Lithium aluminium hydride, and sodium borohydride

Question 57

How to reduce carboxylic acids to primary alcohols?

Answer 57

Use lithium aluminium hydride in an ether solvent, then acidify it with dilute acid

Question 58

How do alkenes and alkynes become more saturated?

Answer 58

Undergo addition reactions

Question 59

When hydrogen adds across a double bond or triple bond, what occurs?

Answer 59

Reduction

Question 60

What does the degree of unsaturation refer to?

Answer 60

The amount in mol of hydrogen gas required to completely saturate one mole of the unsaturated compound.

Question 61

Linear alkenes with one double bond have a degree of saturation of?

Answer 61

1

Question 62

Linear alkynes with one double bond have a degree of unsaturation of?

Answer 62

2

Question 63

Free radical

Answer 63

A chemical entity that has an unpaired electron

Question 64

Does homolytic or heterolytic mean free radical?

Answer 64

Homolytic

Question 65

Why are alkanes unreactive?

Answer 65

The strong C-C and C-H bonds, and the inability to expand their octets

Question 66

Which needs more UV energy to break - oxygen (O2) or ozone (O3)

Answer 66

Oxygen (O2)

Question 67

Are CFC's reactive or unreactive? What bond do they have which makes them so?

Answer 67

Unreactive, carbon-chlorine

Question 68

When are CFC's reactive?

Answer 68

In ozone where UV light breaks the C-Cl bond, to create chlorine radicals

Question 69

The chlorine radicals formed when CFC's break down in ozone, these can react with ozone, to do what to its concentration?

Answer 69

Deplete it

Question 70

What is a nucleophile?

Answer 70

A reactant that forms a bond to its reaction partner, by donating both bonding electrons. They may be neutral or negative ions.

Question 71

What is an electrophile?

Answer 71

A reactant that forms a bond to its reaction partner, by accepting both bonding electrons. They may be neutral or positive ions.

Question 72

Which is more reactive - halogenoalkanes, or alkanes? Why?

Answer 72

Halogenoalkanes, because of the weaker C-Cl, C-Br, and C-I bonds

Question 73

Fluoroalkanes have what everyday use?

Answer 73

Fire extinguishers

Question 74

In the nucleophilic substitution of halogenoalkanes, combining a halogenoalkane with warm dilute NaOH, what forms?

Answer 74

Alcohols

Question 75

The halogen atom, after nucleophilic substitution of halogenoalkanes, has a slightly positive or negative charge?

Answer 75

Negative - the positive charge is on the other atom

Question 76

For a free radical substitution, what two things are needed?

Answer 76

UV light and a halogen