Chemistry June 2012 Things To Remember

Front 1

Chromium configuration

Back 1

1s2 2s2 2p6 3s2 2p6 3d5 4s1

Front 2

Copper configuration

Back 2

1s2 2s2 2p6 3s2 2p6 3d10 4s1

Front 3

Which two d block elements aren't transition elements

Back 3

Scandium and Zinc

Front 4

Co2+ colour

Back 4

pink

Front 5

Cu2+ colour

Back 5

light blue

Front 6

Fe2+ colour

Back 6

pale green

Front 7

Fe3+ colour

Back 7

yellow

Front 8

Co2+ precipitation observations

Back 8

Pink solution forms blue gelatinous precipitate turning beige on standing

Front 9

Cu2+ precipitation observations

Back 9

Pale blue solution forms a pale blue precipitate

Front 10

Fe2+ precipitation observations

Back 10

Pale green solution forms a green precipitates that turns rusty brown on standing

Front 11

Fe3+ precipitation observations

Back 11

Yellow solution forms a rusty brown precipitate

Front 12

[Cu(H2O)6]2+ with ammonia observation

Back 12

pale blue solution initially forms a pale blue precipitate but on excess ammonia forms deep blue solution [Cu(NH3)4(H2O)2]2+

Front 13

[Cu(H2O)6]2+ with Chloride observation

Back 13

Pale blue solution forms yellow/green solution [CuCl4]2-

Front 14

[Co(H20)6]2+ with Chloride

Back 14

Pink solution forms blue solution [CoCl4]2-

Front 15

A larger Kstab means

Back 15

more stable new complex

Front 16

Zero order half life

Back 16

[A] decreases at constant rate, linear, thus half-life decreases with time

Front 17

First order half life

Back 17

[A] halves in equal time interbals, thus half-life is constant

Front 18

Second order half life

Back 18

[A] decreases rapidly but rate of decrease slows down, thus half-life increases with time

Front 19

Zero order on rate-concentration graph

Back 19

Rate unaffected by [A] thus straight horizontal line

Front 20

First order on rate-concentration graph

Back 20

Rate increases by same multiple as change in [A] thus linear line (positive when A is a reactant)

Front 21

Second order on rate-concentration graph

Back 21

Rate increase by square of the multiple of the change in [A] thus parabola (positive when A is a reactant)

Front 22

Fast reaction size of k

Back 22

k is large for a fast reaction

Front 23

effect of catalyst and temperature on k (rate constant)

Back 23

K increases with temperature and catalyst

Front 24

What effects Kc

Back 24

Only temperature effects Kc

Front 25

How can K and Kc be calculated?

Back 25

K can only be calculated through experiment, Kc with balanced equation

Front 26

Definition of neutral solution

Back 26

[H+] = [OH-]

Front 27

Calculate pH of strong acid

Back 27

[HA] = [H+] →ph = -log[H+]

Front 28

Calculate pH of weak acid

Back 28

[H+] = √(Ka[HA]) →ph = -log[H+]

Front 29

Calculate pH of strong base

Back 29

[H+] = Kw/[base] where Kw = 1*10^-14 →ph = -log[H+]

Front 30

Calculate pH of buffer solution

Back 30

[H+] = Ka[HA] / [A-] →ph = -log[H+]

Front 31

How buffer minimises change in pH

Back 31

alkali reacts with H+ eqm then shifts to incrase [H+], conjugate base removes added acid

Front 32

Equivalence point for Strong acid with strong base

Back 32

4-10 thus 7

Front 33

Equivalence point for weak acid with strong base

Back 33

7-10 thus 8.5

Front 34

Equivalence point for strong acid with weak base

Back 34

4-7 thus 5.5

Front 35

How to choose indicator for titration

Back 35

Choose one whose end point pH is as close as possible to the pH of the equivalence point

Front 36

Manganate half equation

Back 36

MnO4- + 8H+ + 5e- → Mn2+ + 4H2O

Front 37

Manganate overall equation and observations

Back 37

MnO4- + 8H+ + 5Fe2+ → Mn2+ + 4H2O + 5Fe3+ (Purple to colourless)

Front 38

Thiosulfate half equation

Back 38

2(S2O3)2- → (S4O6)2- + 2e-

Front 39

Thiosulfate overall equation and observations

Back 39

I2 + 2(S2O3)2- → 2I- + (S4O6)2- (Brown to colourless)

Front 40

What is added to make thiosulfate end point obvious and observation

Back 40

Starch colour goes from blue/black to colourless

Front 41

Standard hydrogen half cell equation

Back 41

2H+ + 2e- → H2

Front 42

More negative Eᶱ means

Back 42

easily oxidised

Front 43

For a feasibile redox reaction overall Eᶱ must be

Back 43

positive and generally >0.4V

Front 44

Lattice enthalpy values are what and indicate what?

Back 44

Always negative (Exothermic), the more negative the stronger the lattice

Front 45

Lowest level on Born-Haber cycle

Back 45

The solid ionic lattice

Front 46

For enthalpy change of solution Born-Haber cycle

Back 46

Solid on bottom, aqueous ions middle and gaseous ions stop level

Front 47

Higher entropy means

Back 47

more disorder/randomness in the system

Front 48

Free energy change

Back 48

ΔG = ΔH - TΔS for feasibility ΔG > 0

Front 49

In ΔG calculations what must be done to ΔS

Back 49

ΔS/1000 so units become kJ K-1 mol-1