Chemistry extension

Question 1

Why do chemical reactions violate thermodynamics?

Answer 1

ΔG = ΔH - TΔS

Question 2

Why can redox reactions be impossible?

Answer 2

AG^o = -RT(K_eq) = -nFE^o_cell

Question 3

The octet rule

Answer 3

The number of electrons in a shell is 2n²

Question 4

What does polar mean?

Answer 4

Soluble in water

Question 5

The higher the lattice enthalpy…

Answer 5

The stronger the bond

Question 6

F (lattice enthalpy)

Answer 6

(KQ₁(charge on ion)Q₂)/r²(size of ion)

Question 7

Reduction (oxygen,electrons,hydrogen,o.s.)

Answer 7

-,+,+,-

Question 8

Oxidation (oxygen,electrons,hydrogen,o.s.)

Answer 8

+,-,-,+

Question 9

Balancing acid half equations

Answer 9

• Any atoms not O or H
• O using water
• H using H⁺
• Charge using electrons

Question 10

Balancing alkali half equations

Answer 10

• Any atoms not O or H
• OH using O
• H using water
• Charge using electrons

Question 11

Oxidation state of F

Answer 11

-1

Question 12

Oxidation state of O

Answer 12

-2 (except when bonded to F or O)

Question 13

Oxidation state of H

Answer 13

+1 (except when bonded to a metal)

Question 14

Oxidation state of a metal

Answer 14

Its charge

Question 15

The sum of o.s.

Answer 15

0 or the charge on the ion

Question 16

2 pair bonding angle

Answer 16

180^o - linear

Question 17

3 pair bonding angle

Answer 17

120^o - trigimal planar

Question 18

4 pair bonding angle

Answer 18

109.5^o - tetrahedral

Question 19

5 pair bonding angle

Answer 19

90^o and 120^o - trigimal biplanar

Question 20

6 pair bonding angle

Answer 20

90^o - octahedral

Question 21

2 bonding and 1 non-bonding

Answer 21

<120^o - bent or V-shaped

Question 22

3 bonding and 1 non-bonding

Answer 22

107^o - trigonal pyramidal

Question 23

2 bonding and 2 non-boning

Answer 23

104.5^o - bent or V-shaped

Question 24

4 bonding and 1 non-bonding

Answer 24

See-saw

Question 25

3 bonding and 2 non-bonding

Answer 25

T-shaped

Question 26

2 bonding and 3 non-bonding

Answer 26

Linear

Question 27

Temperature is directly proportional to…

Answer 27

average KE of particles

Question 28

First law of thermodynamics (Hess’s law)

Answer 28

Energy is always conserved

Question 29

Second law of thermodynamics

Answer 29

Entropy (disorder) always increases irrespective of route

Question 30

Third law of thermodynamics

Answer 30

Entropy of a system approaches 0 as temp approaches 0K

Question 31

ΔHf

Answer 31

Enthalpy of formation is ΔH when one mole of compound forms from its constituent elements in their standards states, under standard conditions (theoretical)

Question 32

ΔHc

Answer 32

Enthalpy change when 1 mole of a substance burns completely in oxygen (measureable)

Question 33

ΔHc(O)

Answer 33

0

Question 34

ΔHf(pure element)

Answer 34

0

Question 35

ΔH_at

Answer 35

Atomisation - ΔH of elements in standard state to 1 mole of gaseous atoms

Question 36

IE

Answer 36

Ionisation - ΔH of energy to remove 1 mole of electrons to form 1 mole of gaseous ions (+ve)

Question 37

EA

Answer 37

Electron affinity - ΔH of energy to add 1 mole of electrons to form 1 mole of gaseous ions (-ve)

Question 38

ΔH_lat

Answer 38

Lattice enthalpy - ΔH of energy to break 1 mole of ionic compound into its constituent gaseous ions

Question 39

ΔH of solution

Answer 39

1 mole of ionic compound into aqueous solution of infinite dilution

Question 40

ΔH_lat

Answer 40

((N_a(Avagadro’s number)M(Madelung constant)Z₁Z₂(charges)e²)/4πE_o(Permeability of free space)r_o(Distance between ions))(1-1/n(Born exponent))

Question 41

NMR

Answer 41

• Number of peaks = chemical environment
• Area under peaks = ratio of atoms in those environments

Question 42

IR

Answer 42

• ≈1700cm^-1 CO double bond
• ≈3000cm^-1 and wide OH single bond

Question 43

Standards enthalpy change of reaction

Answer 43

Σ(Δ_tH^θproducts)-Σ(Δ_tH^θreactants)

Question 44

What is an aldehyde?

Answer 44

A molecule with the carbonyl group at the end of the chain

Question 45

What is a ketone?

Answer 45

A molecule with the carbonyl group bonded to a carbon atom either side

Question 46

How do you produce aldehydes?

Answer 46

Heat a primary alcohol with oxidising agent (K₂Cr₂O₇ acidified with H₂SO₄) and distil it

Question 47

How do you produce ketones?

Answer 47

Heat a secondary alcohol with oxidising agent (K₂Cr₂O₇ acidified with H₂SO₄)

Question 48

Can aldehydes be oxidised?

Answer 48

Yes, to produce carboxylic acids

Question 49

Can ketones be oxidised?

Answer 49

They are very resistant to oxidisation

Question 50

Positive Tollens’ Reagent result

Answer 50

The aldehyde is oxidised, reducing the silver ions to solid silver which creates a silver mirror

Question 51

Negative Tollens’ Reagent result

Answer 51

When gently warmed with a ketone, no silver mirror will be seen as the ketone cannot be oxidised

Question 52

Positive Fehling’s solution result

Answer 52

The aldehyde will be oxidised and the blue Cu²⁺ ions reduced to Cu⁺ turning it brick red

Question 53

Negative Fehling’s solution result

Answer 53

The ketone will not be oxidised so no change occurs

Question 54

What colour change can be seen in ketones when heating with potassium dichromate?

Answer 54

None

Question 55

What colour change can be seen in aldehydes when heating with potassium dichromate?

Answer 55

Orange to green as the aldehyde reacts to form a carboxylic acid

Question 56

nm

Answer 56

1*10_-9

Question 57

mm

Answer 57

1*10_-3

Question 58

cm

Answer 58

1*10_-2

Question 59

dm

Answer 59

1*10_-1

Question 60

km

Answer 60

1*10₃

Question 61

Mm

Answer 61

1*10₆

Question 62

Gm

Answer 62

1*10₉

Question 63

µm

Answer 63

1*10^-6

Question 64

pm

Answer 64

1*10^-12