Chemistry: Elements From The Sea

Front 1

During electrolysis of Aqueous NaCl, what is produced at each electrode?

Back 1

Reduction at cathode producing oxygen: 2H2O > 4H+ + O2 + 4e-

Oxidation at anode producing halide: 2Cl- > 2Cl + 2e-

Front 2

What does the cathode attract?

Back 2

Positive cations as it's negative

Front 3

What does the anode attract?

Back 3

Anions as they are positive

Front 4

What is the half equation for hydrogen formed at the cathode? And when does hydrogen form at the cathode?

Back 4

2H+ + 2e- > H2

Formed when acids are in solution

Front 5

What is the half equation for hydrogen formed at the cathode? And when does hydrogen form at the cathode?

Back 5

2H+ + 2e- > H2

Formed when acids are in solution

Front 6

When is oxygen formed at the cathode during electrolysis of an aqueous ionic compound? What is the equation?

Back 6

Oxygen formed when a group 1, 2 or aluminium metal is in the ionic compound.

2H2O > 4H+ + O2 + 4e-

Front 7

When are hydroxides produced at the anode during the electrolysis of aqueous ionic compounds? What is the equation?

Back 7

Produced if the salt is a sulfate or nitrate

2H2O + 2e- > H2 + 2OH-

Front 8

When is oxygen produced at the anode during the electrolysis of aqueous ionic compounds? Give the half equation

Back 8

When there are hydroxides present in the compound.

4OH- > O2 + 2H2O + 2e-

Front 9

In an aqueous ionic compound (CaCl2) undergoing electrolysis; what is produced at the anode and what is produced at the cathode?

Back 9

Chloride a halide so a halogen produced at the anode: 2Cl- > Cl2 + 2e-

At the cathode oxygen will be produced as calcium is a group 2 metal. So, 2H2O > 4e- + O2 + 4H+

Front 10

How do you calculate atom economy?

Back 10

Total relative formula mass of useful products / total relative formula mass of all products x 100

Front 11

How do you calculate atom economy?

Back 11

Total relative formula mass of useful products / total relative formula mass of all products x 100

Front 12

Why is 100% atom economy desirable?

Back 12

It produces only intended products. An excess of waste products increase pollution and cost to dispose of.

Front 13

How do you calculate atom economy?

Back 13

Total relative formula mass of useful products / total relative formula mass of all products x 100

Front 14

Why is 100% atom economy desirable?

Back 14

It produces only intended products. An excess of waste products increase pollution and cost to dispose of.

Front 15

If the oxidation state of an element has increased (become more positive), what has happened?

Back 15

It has been oxidised

Front 16

What is the trend in volatility of group 7 (halogens)?

Back 16

It decreases as you go down the group. So fluorine most volatile so has lowest boiling point

Front 17

What is the trend in volatility of group 7 (halogens)?

Back 17

It decreases as you go down the group. So fluorine most volatile so has lowest boiling point

Front 18

Definition of volatility

Back 18

An elements susceptibility to change quickly from liquid or solid to a gas

Front 19

What does chlorine look like at RTP?

Back 19

Pale green gas

Front 20

What does chlorine look like at RTP?

Back 20

Pale green gas

Front 21

Appearance of bromine at RTP

Back 21

Red-brown liquid

Front 22

What does chlorine look like at RTP?

Back 22

Pale green gas

Front 23

Appearance of bromine at RTP

Back 23

Red-brown liquid

Front 24

What colour vapour would bromine give off?

Back 24

Orange vapour

Front 25

What does chlorine look like at RTP?

Back 25

Pale green gas

Front 26

Appearance of bromine at RTP

Back 26

Red-brown liquid

Front 27

What colour vapour would bromine give off?

Back 27

Orange vapour

Front 28

Appearance of iodine at RTP

Back 28

Grey solid which turns to purple has of heated

Front 29

What does chlorine look like at RTP?

Back 29

Pale green gas

Front 30

Appearance of bromine at RTP

Back 30

Red-brown liquid

Front 31

What colour vapour would bromine give off?

Back 31

Orange vapour

Front 32

Appearance of iodine at RTP

Back 32

Grey solid which turns to purple has of heated

Front 33

Compare the solubility of halogens in organic solvents and water

Back 33

Very soluble in non polar solvents. Much less soluble in water.

Front 34

What does chlorine look like at RTP?

Back 34

Pale green gas

Front 35

Appearance of bromine at RTP

Back 35

Red-brown liquid

Front 36

What colour vapour would bromine give off?

Back 36

Orange vapour

Front 37

Appearance of iodine at RTP

Back 37

Grey solid which turns to purple has of heated

Front 38

Compare the solubility of halogens in organic solvents and water

Back 38

Very soluble in non polar solvents. Much less soluble in water.

Front 39

Appearance of chlorine, bromine and iodine in when aqueous

Back 39

Chlorine: pale yellow

Bromine: orange

Iodine: brown

Front 40

What does chlorine look like at RTP?

Back 40

Pale green gas

Front 41

Appearance of bromine at RTP

Back 41

Red-brown liquid

Front 42

What colour vapour would bromine give off?

Back 42

Orange vapour

Front 43

Appearance of iodine at RTP

Back 43

Grey solid which turns to purple has of heated

Front 44

Compare the solubility of halogens in organic solvents and water

Back 44

Very soluble in non polar solvents. Much less soluble in water.

Front 45

Appearance of chlorine, bromine and iodine in when aqueous

Back 45

Chlorine: pale yellow

Bromine: orange

Iodine: brown

Front 46

When aqueous chloride ions are added to silver nitrate what colour precipitate of formed?

Back 46

White - it will dissolve in dilute ammonia

Front 47

What does chlorine look like at RTP?

Back 47

Pale green gas

Front 48

Appearance of bromine at RTP

Back 48

Red-brown liquid

Front 49

What colour vapour would bromine give off?

Back 49

Orange vapour

Front 50

Appearance of iodine at RTP

Back 50

Grey solid which turns to purple has of heated

Front 51

Compare the solubility of halogens in organic solvents and water

Back 51

Very soluble in non polar solvents. Much less soluble in water.

Front 52

Appearance of chlorine, bromine and iodine in when aqueous

Back 52

Chlorine: pale yellow

Bromine: orange

Iodine: brown

Front 53

When aqueous chloride ions are added to silver nitrate what colour precipitate of formed?

Back 53

White - it will dissolve in dilute ammonia

Front 54

What colour precipitate will form when silver bromide comes out of solution?

Back 54

Cream - this will dissolve in excess conc. ammonia

Front 55

What does chlorine look like at RTP?

Back 55

Pale green gas

Front 56

Appearance of bromine at RTP

Back 56

Red-brown liquid

Front 57

What colour vapour would bromine give off?

Back 57

Orange vapour

Front 58

Appearance of iodine at RTP

Back 58

Grey solid which turns to purple has of heated

Front 59

Compare the solubility of halogens in organic solvents and water

Back 59

Very soluble in non polar solvents. Much less soluble in water.

Front 60

Appearance of chlorine, bromine and iodine in when aqueous

Back 60

Chlorine: pale yellow

Bromine: orange

Iodine: brown

Front 61

When aqueous chloride ions are added to silver nitrate what colour precipitate of formed?

Back 61

White - it will dissolve in dilute ammonia

Front 62

What colour precipitate will form when silver bromide comes out of solution?

Back 62

Cream - this will dissolve in excess conc. ammonia

Front 63

What colour will silver bromide compounds go when filtered out of solution?

Back 63

Yellow - won't dissolve in ammonia

Front 64

How can you tell Cl-, Br- and I- ions apart?

Back 64

Add silver nitrate. They all give different colour precipitates: Cl- (white), Br- (cream) and I- (yellow).

If doesn't dissolve in ammonia then iodide. If dissolves in diluted ammonia then chloride. If dissolves in excess of conc. ammonia then bromide.

Front 65

If hydrogen halides are exposed to moist air what is observed?

Back 65

Steamy fumes

Front 66

If hydrogen halides are exposed to moist air what is observed?

Back 66

Steamy fumes

Front 67

If ammonia and hydrogen halides react what is observed?

Back 67

Copious amounts of white steamy fumes

Front 68

If hydrogen halides are exposed to moist air what is observed?

Back 68

Steamy fumes

Front 69

If ammonia and hydrogen halides react what is observed?

Back 69

Copious amounts of white steamy fumes

Front 70

H-F + NH3 > NH4F

What acts as the base and what acts as the acid here?

Back 70

Ammonia- base

Hydrogen ion - acid

Front 71

Definition of dynamic equilibrium

Back 71

The state where the forward reaction is happening at the same rate of as the reverse reaction. The results showing that the conc. of the reactants and products are constant within a closed system

Front 72

Definition of dynamic equilibrium

Back 72

The state where the forward reaction is happening at the same rate of as the reverse reaction. The results showing that the conc. of the reactants and products are constant within a closed system

Front 73

Definition of closed system

Back 73

A situation where no substances can enter or leave the system. e.g. Sealed tank

Front 74

Where would the position of equilibrium lie if there concentration of products was higher than that of reactants?

Back 74

To the right

Front 75

What factors out of these can affect: pressure, concentration, catalysts and temperature

Back 75

Only temperature

Front 76

What factors out of these can affect: pressure, concentration, catalysts and temperature

Back 76

Only temperature

Front 77

What is the effect on Kc when the pressure of the closed system is increased?

Back 77

The position moves to the side of the reaction with less miles of gas

Front 78

What factors out of these can affect: pressure, concentration, catalysts and temperature

Back 78

Only temperature

Front 79

What is the effect on Kc when the pressure of the closed system is increased?

Back 79

The position moves to the side of the reaction with less miles of gas

Front 80

What happens to the position of equilibrium when the pressure is decreased?

Back 80

It will move to the side of the reaction with more moles of gas

Front 81

What factors out of these can affect: pressure, concentration, catalysts and temperature

Back 81

Only temperature

Front 82

What is the effect on Kc when the pressure of the closed system is increased?

Back 82

The position moves to the side of the reaction with less miles of gas

Front 83

What happens to the position of equilibrium when the pressure is decreased?

Back 83

It will move to the side of the reaction with more moles of gas

Front 84

What happens to the position of equilibrium when the temperature is increased?

Back 84

Will move in the direction which involves an endothermic change. To decrease temperature as much a possible.

Front 85

What happens to the position of equilibrium when the temperature is decreased?

Back 85

Position will move to which ever direction has an exothermic change. Increasing energy.

Front 86

What happens to the position of equilibrium when the temperature is decreased?

Back 86

Position will move to which ever direction has an exothermic change. Increasing energy.

Front 87

What is the effect of a catalyst on equilibrium?

Back 87

No effects. It simply speeds up reaction.

Front 88

What is the effect of increasing the rate of reaction by increasing concentration?

Back 88

More particles per unit volume. So a higher frequency of collisions per second. So higher rate of reaction.

Front 89

What is the effect of increasing the rate of reaction by increasing concentration?

Back 89

More particles per unit volume. So a higher frequency of collisions per second. So higher rate of reaction.

Front 90

Effect on increasing pressure on rate of reaction

Back 90

More particles per unit volume. Higher frequency of collisions with combined kinetic energy exceeding the activation enthalpy per second. Increased rate of reaction.

Front 91

Effect of increased surface area in rate of reaction

Back 91

Greater proportion of particles exposed for collision with combined kinetic energy exceeding the activation enthalpy. More collision per second. Increased rate of reaction.

Front 92

Effect of temperature on rate of reaction

Back 92

Average kinetic energy of the reactant particles increased. So combined kinetic energy of collisions will involve a combined kinetic energy that's equal too or greater than the activation enthalpy. Increased rate of reaction. Also more collisions per second as higher kinetic energy induced higher velocity.

Front 93

Effect of temperature on rate of reaction

Back 93

Average kinetic energy of the reactant particles increased. So combined kinetic energy of collisions will involve a combined kinetic energy that's equal too or greater than the activation enthalpy. Increased rate of reaction. Also more collisions per second as higher kinetic energy induced higher velocity.

Front 94

Effect of a catalyst on rate of reaction

Back 94

Provides and alternative pathway with a lower activation enthalpy. A higher proportion of collisions will involve a combined kinetic energy that is equal to or greater than the activation enthalpy so a higher rate of reaction

Front 95

Write the rate equation

Back 95

Rate = change in concentration / time taken

Front 96

What is rate measured in?

Back 96

mol dm-3 s-1

Front 97

What is rate measured in?

Back 97

mol dm-3 s-1

Front 98

How can colorimetry be used to measure the rate of reaction by measuring concentration change? Give the procedure

Back 98

Using a sustainable filter find the complimentary colour to the coloured substance in the equation. Zero the colour colorimeter using distilled water then calibrate it. Make up some solutions of the substance with known concentrations. measure the absorbance of the coloured substance at certain time intervals. Then plot a calibration graph, which is absorbance over concentration. After this plot a progress graph of time over concentration then draw a tangent at X equals zero and measure the gradient.