inorganic chemistry

Question 1

how do group one metals react with water (Li, Na, K)

Answer 1

vigorously
produce hydrogen
form metal hydroxide solution (alkaline)
metal +water -> metal hydroxide + hydrogen

Question 2

how do group one metals react with oxygen in air (Li, Na, K)

Answer 2

form metal oxides

this is why they tarnish when left in air (form layer of metal oxide)

Question 3

explain the trend in reactivity in group 1

Answer 3

gets more reactive as you go down because:
1) the distance from the nucleus (where the positive charge is) and the outermost electron increases
2) there is more shielding
3) both these things outweigh the increase in the number of protons in the nucleus
therefore it is easier to lose the outermost electron

Question 4

describe the trend in physical properties of group 7 elements

Answer 4

as you go down they get darker and have higher boiling points (so at top light gases and at bottom dark solids)

Question 5

what colour and state is Cl at room temperature

Answer 5

green gas (poisonous)

Question 6

what colour and state is Br at room temperature

Answer 6

red-brown liquid, gives off orange vapour at room temp (poisonous)

Question 7

what colour and state is l at room temperature

Answer 7

dark grey crystalline solid, gives of purple vapour when heated

Question 8

explain the chemical trends in group 7 elements

Answer 8

as you go down, they get less reactive because:
1) the atomic radius increases
2) there is greater shielding
3) both these things outweigh the increase in the number of protons in the nucleus
therefore it is harder to attract an electron

Question 9

describe displacement reactions with halogens

Answer 9

more reactive halogens displace less reactive ones from a compound

Question 10

what makes up air

Answer 10

78% nitrogen
21% oxygen
1% argon
0.04% co2

Question 11

decsribe the thermal decompostion of metal carbonates

Answer 11

metal carbonate -> metal oxide + carbon dioxide

eg: copper carbonate (green powder) -> copper oxide (black) + co2

Question 12

list the reactivity series

Answer 12

K
Na
Li
Ca
Mg
Al
Zn
Fe
Cu
Ag
Au

Question 13

what is the reaction of metals with acids

Answer 13

acid +metal -> salt + hydrogen

Question 14

what is the reaction of metals with water

Answer 14

reactive metals: metal+ water-> metal hydroxide+ hydrogen

less reactive: metal + steam -> metal oxide + hydrogen

Question 15

what is the word equation for rusting

Answer 15

iron +water-> hydrated iron(iii)oxide (rust)

Question 16

what is oxidation

Answer 16

the loss of electrons or gain of oxygen

Question 17

what is reduction

Answer 17

the gain of electrons or loss of oxygen

Question 18

what is a redox reaction

Answer 18

where reduction and oxidation happen simultaneosly

Question 19

what is an oxidising agent

Answer 19

accepts the electron; gets reduced

Question 20

what is a reducing agent

Answer 20

donates the electron; gets oxidised

Question 21

what colour is litmus in acid/alkali

Answer 21

red= acid; purple=neutral; blue= alkali

Question 22

what colour is phenolphthalein in acid/alkali

Answer 22

colourless= acid; pink= alkali

Question 23

what colour is methyl orange in acid/alkali

Answer 23

red= acid; yellow= alkali

Question 24

what is an acid

Answer 24

a source of H+ IONS (proton donors)

Question 25

what is an alkali

Answer 25

a soluble base; source of OH- ions ( proton acceptors)

Question 26

which ions make soluble ionic compounds

Answer 26

sodium, potassium, ammonium

Question 27

are nitrates soluble

Answer 27

yes

Question 28

are cholrides soluble

Answer 28

yes, except silver and lead ii

Question 29

are sulfates soluble

Answer 29

yes, except barium, calcium, lead

Question 30

are carbonates soluble

Answer 30

no, except na, k, nh4

Question 31

are hydroxides soluble

Answer 31

no, except na, k, nh4 (and Ca(OH)2 IS SLIGHTLY soluble)

Question 32

make a soluble salt

Answer 32

``` react an acid with an insoluble base heat acid in water bath add base stop adding when solid stays at bottom filter out excess solid heat gently then leave to crystalise ```

Question 33

test for oxygen

Answer 33

relights glowing splint

Question 34

test for H

Answer 34

makes a squeaky pop with a lit splint

Question 35

test for co2

Answer 35

turns limewater cloudy

Question 36

ammonia test

Answer 36

turns damp red litmus paper blue + smells

Question 37

Test for chlorine

Answer 37

bleaches damp blue litmus paper (turns white)

Question 38

flame test for Li+

Answer 38

red

Question 39

flame test for Na+

Answer 39

yellow

Question 40

flame test for K+

Answer 40

lilac

Question 41

flame test for Ca2+

Answer 41

orange-red

Question 42

flame test for Cu2+

Answer 42

blue green

Question 43

test for NH4+

Answer 43

add sodium hydroxide then test for ammonia gas (damp red litmus goes blue)

Question 44

test for Cu2+

Answer 44

add sodium hydroxide and BLUE PRECIPITATE forms

Question 45

test for Fe2+

Answer 45

add sodium hydroxide and SLUDGY GREEN PRECIPITATE forms

Question 46

test for Fe3+

Answer 46

add sodium hydroxide and RED/BROWN PRECIPITATE forms

Question 47

test for Cl-

Answer 47

add dilute nitric acid then silver nitrate solution: white precipitate

Question 48

test for Br-

Answer 48

add dilute nitric acid then silver nitrate solution: cream precipitate

Question 49

test for I-

Answer 49

add dilute nitric acid then silver nitrate solution: yellow precipitate

Question 50

test for water

Answer 50

anhydrous copper sulfate = white; hydrated copper sulfate= blue

Question 51

test for pure water

Answer 51

boils at 100 degrees celcius

Question 52

Describe how to carry out an acid alkali titration ( with known volume of acid)

Answer 52

Using a Pipette and Pipette filler, add 25 cm3 of alkali to a conical flask with some indicator Fill a burette with the acid Add the acid to the alkali slowly, swirling it regularly When the colour changes record the volume Repeat until you get the same result

Question 53

How to make an insoluble salt

Answer 53

Pick two soluble salts Eg to make lead Sulfate, use lead nitrate and magnesium Sulfate Dissolve equal amounts of each salt in pure water Mix the two solutions and stir Filter out the precipitate Wash and dry

Question 54

How to make a soluble salt using titration

Answer 54

Using a Pipette and Pipette filler, add 25 cm3 of alkali to a conical flask with some indicator Fill a burette with the acid Add the acid to the alkali slowly, swirling it regularly When the colour changes record the volume Repeat without the indicator Evaporate off some of the water Leave to crystallise Filter off the solid Dry it

Question 55

How to make a soluble salt (not titration)

Answer 55

Use acid + insoluble base Heat the acid in a water bath (in a fume cupboard) Add the base to the acid until in excess (when solid is left) Filter off the excess solid Heat solution gently Leave to cool and crystallise Filter and dry

Question 56

What colour flame does sulfur burn with

Answer 56

Blue

Question 57

What happens to HCL in water

Answer 57

Disassociates into H+ ions and CL- ions | Litmus turns red

Question 58

What happens to HCL in methylbenzene

Answer 58

Doesn’t disassociate | Litmus stays blue

Question 59

Name an iron ore

Answer 59

Haematite | Magnetite

Question 60

How does limestone remove the impurity silica from a furnace

Answer 60

Limestone (calcium carbonate) decomposes to form CaO | CaO reacts with silica to form calcium silicate

Question 61

Describe how aluminium is extracted from purified aluminium oxide

Answer 61

``` Aluminium is extracted by electrolysis Aluminium added to cryolite Electrolyte molten Carbon/graphite electrodes used Aluminium ions discharged/ aluminium formed at cathode ```