Chem

Question 1

Reactivity down Gps 1 and 2

Answer 1

Increases

Question 2

Reactivity down Gps 6 and 7

Answer 2

Decreases

Question 3

Colour when Li is burnt

Answer 3

Crimson red

Question 4

Colour when Na is burnt

Answer 4

Yellow -orange

Question 5

Colour when K is ignited

Answer 5

Self ignited to burn w/ a lilac flame

Question 6

Buckminster fullerene

Answer 6

C 60

Question 7

Ionic eqn for acid + alkali

Answer 7

H+ + OH- —> H2O

Exothermic

Question 8

Ionic eqn for acid and carbonate

Answer 8

2H+ + CO3^2- —-> H2O + CO2

Question 9

Ionic eqn acid and ammonia

Answer 9

H+ + NH3 —> NH4+

Question 10

Physical properties of alkali metals

Answer 10

Low mp and bp - decrease down group (weaker metallic bonding)
Low densities - increase down gp
Soft and become softer down gp
Good conductors of heat and electricity

Question 11

Chemical properties of alkali metals

Answer 11

V reactive - stored in oil to prevent reactions
When exposed to air - react w/ O2 and tarnish
Reactivity increases down group

Question 12

Li, Na, K reactions w/ water

Answer 12

Float, moving and fizzing
Produces H2 (squeaky pop)
K - H2 spontaneously ignites and burns lilac
Soluble hydroxide forms

Question 13

Properties of halogens

Answer 13

Coloured vapours
Low mp and bp, increase down group
Poor conductors of heat and electricity
Reactivity decreases (displacement)

Question 14

Halogens at RTP

Answer 14

F - pale yellow gas
Cl - Yellow-green gas
Br - Red/brown volatile liquid w/ orange vapour
I - Grey shiny solid, purple vapour when heated

Question 15

Properties of noble gases

Answer 15

Colourless gases at RTP
V. low mp and bp - increase down the group
Density increases down group

Question 16

Metals and acid

Answer 16

Salt and H2

Only reacts if metal is more reactive than H2

Question 17

SO2 (g) + H2O

Answer 17

H2SO3 (aq)

Question 18

2NO2 (g) + H2O

Answer 18

HNO3 + HNO2

Question 19

Separating funnel

Answer 19

Sepeartes two immiscible liquids by density

Question 20

Simple distillation

Answer 20

Separates substances by bp, usually solvent from a solution, leaving solute

Question 21

Fractional distillation

Answer 21

Separates miscible liquids from a mixture

Similar setup to simple distillation but has fractionating column w/ glass beads

Question 22

Evaporation and Crystallisation

Answer 22

Separates solvents from solute using diff in bp and/or volatility but target is solute
Heated gently til crystals begin to form (crystallising point)

Question 23

Why isn’t it recommended to heat to dryness

Answer 23

Some solids may decompose if heated too strongly

Question 24

Centrifugation

Answer 24

Separates heterogenous mixtures based on diff in particle mass
Encourages settling by spinning at high speed, heaviest settle first
Supernatant decanted into new tube and spun again

Question 25

Separating gas-gas mixtures

Answer 25

Centrifugation or cryogenic distillation

Question 26

Why is dc used in electrolysis

Answer 26

So current passes in one direction only

Question 27

Cathode

Answer 27

Electrons flow from external circuit and enter via this -ve electrode Cations are attracted and reduced (metal if LESS reactive than H2)

Question 28

Anode

Answer 28

e- leave cell via this +ve electrode Anions attracted ad oxidised (non-metal) If complex ion e.g. SO4 ^2-, NO3^- O2 is formed from OH-

Question 29

Reactivity series

Answer 29

``` Potassium Sodium Lithium Calcium Magnesium Aluminium CARBON Zinc Iron HYDRROGEN Copper Silver Gold ```

Question 30

Electroplating

Answer 30

-ve electrode: object to be plated +ve electrode: coating metal Electrolyte - sol of coating metal e.g. metal sulphate or nitrate Conc of metal ions in electrolyte remains unchanged

Question 31

Purifying copper

Answer 31

Impure copper - anode Pure copper - cathode Copper (II) sulfate solution - electrolyte

Question 32

Small molecules in crude oil

Answer 32

Low bp V volatile Flow easily Ignite easily

Question 33

Large molecules in crude oil

Answer 33

High bp Not volatile V. viscous Doesn't ignite easily

Question 34

Biodegradable polymers

Answer 34

Break doen after intended use to produce natural products e.g. CO2, N2, H2O Usually done by microorganisms or enzymes Often contain ester or amide linkages

Question 35

Extracting metals

Answer 35

If less reactive than carbon then carbon can be used (or CO) | If more reactive electrolysis is used, split w/ electricity and metal attracted to cathode

Question 36

Extracting copper

Answer 36

Phytomining (plants) | Bioleaching (bacteria)

Question 37

Al

Answer 37

Lightweight Soft and malleable Corrosion resistant and non-toxic Uses in aeroplanes (strong and low density), conductor cables, foil, utensils

Question 38

Ag

Answer 38

Best thermal ane electrical conductor Antimicrobial and non-toxic: useful in med Silver nanoparticles inhibit odour in socks

Question 39

Ti

Answer 39

Strong as steel but less dense Important alloying agent Can withstand extremes of temp - aircraft, spacecraft and missilies

Question 40

Testing for Cl2 gas

Answer 40

Damp blue litmus turns red and then is bleached

Question 41

Anion tests

Answer 41

Carbonates - dilute acids Sulphates - BaCl2 in the presence of dilute HCl Halides - AgNO3 (aq)

Question 42

Cation tests (0.1 moldm-3) using NaOH

Answer 42

Al^3+, Ca^2+, Mg^2+ - white pp Cu^2+ - blue ppt Fe^2+ - green ppt Fe^3+ - brown ppt

Question 43

Flame test

Answer 43

``` Li - crimson red Na - yellow orange K - lilac Ca - red orange Cu - green ```

Question 44

Testing for water w/ anhydrous copper (II) sulphate

Answer 44

White --> blue | CuSO4 (s) + 5 H2O ---> CuSO4.5H2O

Question 45

Testing for O2

Answer 45

Blow out burning split, if oxygen present splint relights

Question 46

SO2

Answer 46

Poisonous, odourless, acidic gas w/ choking smell Combine w. water --> H2SO4 (aid rain) Erodes stonework, increases metal corrosion increases leaching

Question 47

Oxides of nitrogen

Answer 47

React w. water and oxygen in rain ---> HNO3 (acid rain) | Toxic gases and can trigger asthma attacks