# data[].attributes.body
Alkali Metals are group 1 metals and include :  Lithium, Sodium, Potassium, Rubidium, Caesium and Francium.
-They have characteristic properties due to the single electron in their outer shell. All of the metals in group one react vigorously with water to create an alkaline solution and hydrogen.

# data[].attributes.body
-The Reactivity of Group 1 Metals will increase down the group
-They all react with oxygen to create an oxide.
- More bubbles with reaction with water = more vigorous reaction = more reactive
alkali metal

# data[].attributes.body
-increase in reactivity down the group applies for any reaction
-Lithium will be the least reactive at the top and Francium will be the most reactive at the bottom

# data[].attributes.body
-Down the group – easier to lose electrons and form cations
-It is easier to lose electrons due to the increase in electron shells as you go down
the group. This means decreases attraction between the positively charged nucleus and the negatively charged outer shell electrons, which can then be lost more easily

# data[].attributes.body
Halogens: Group 7 non-metals, include: Fluorine, Chlorine, Bromine, Iodine and Astatine.They are diatomic
Chlorine is a yellow-green gas
Bromine is a red-brown liquid
Iodine is a black solid
There is a trend in state from gas to liquid to solid down the group

# data[].attributes.body
-There is a trend in state from gas to liquid to solid down the group
- this is because the melting and boiling points increase as you go down the group
- from this, you can predict that any halogens above chlorine will be gases (their
boiling points will be even lower), and any below iodine will be solids (their
melting points will be even greater)

# data[].attributes.body
A more reactive halogen can displace a less reactive in an aqueous solution of its
salt.
E.g. Chlorine will displace bromine if you bubble the gas through a solution of
potassium bromide:
Chlorine + Potassium Bromide → Potassium Chloride + Bromine
-chlorine will displace bromine and iodine
- bromine will displace iodine but not chlorine
- iodine can replace neither chlorine or iodine
- This happens because as you go down the group, the reactivity of halogens
decreases.

# data[].attributes.body
The halogens react by gaining an electron in their outer shell, as you go down the
group:
- outer shell becomes further from the nucleus
- electron shielding increases
- attraction decreases between nucleus and outer electrons
- electrons are gained less easily
-halogens become less reactive

# data[].attributes.body
composition of air: 78% nitrogen, 21% oxygen, 0.9% argon and 0.037% carbon dioxide

# data[].attributes.body
-100 cm3 of air passed from side to side over copper that was being heated with a Bunsen burner
-All oxygen in air will react with copper
- As it is passed, the volume of air will decrease
- Continued until the volume stops decreasing, then record the volume of remaining air
- There would be about 80cm3 left, showing that 20cm3 of the original 100cm3 of air was oxygen

# data[].attributes.body
Combustion is an example of oxidation
-In an oxidation reaction, a substance gains oxygen
- Metals and non-metals can take part in these reactions
- E.g. magnesium + oxygen -> magnesium oxide
2Mg + O2 -> 2MgO
-E.g. sulfur + oxygen -> sulfur dioxide
S + O2 -> SO2
- E.g. hydrogen + oxygen -> water
2H2 + O2 -> 2H2O

# data[].attributes.body
Metal carbonate –(heat)-> metal oxide + carbon dioxide
- E.g. copper (II) carbonate –(heat)-> copper (II) oxide + carbon dioxide :
CuCO3 -> CuO + CO2

# data[].attributes.body
The greenhouse effect:

1. The Sun emits rays that enter the Earth’s Atmosphere

2. The heat is emitted back from the Earth’s surface

3. Some heat is reflected back out into Space

4. But some heat is absorbed by Greenhouse gasses Such as Carbon Dioxide and is trapped within the Earth’s Atmosphere so causes the Earth’s average temperature to rise as a result

Greenhouse gases include: water vapour, CO2 & CH4
-Global warming is an ‘enhanced greenhouse effect’ and contributes majorly to climate change
some consequences:

Climate change due to increase in Earth’s temperature

Water levels will rise as glaciers will melt because of high temperatures, causes flooding in low-lying countries

# data[].attributes.body
same as 2.10

# data[].attributes.body
Displacement Reaction: A reaction in which a more reactive metal replaces a less reactive one

Reactivity of metals increases up the reactivity series

This means that a metal will displace another metal that is below it in the reactivity series

▪ You can see if one metal is more reactive than another by using displacement
reactions:
▪ More reactive metal gradually disappears as it forms a solution
▪ Less reactive metal coats the surface of the more reactive metal

# data[].attributes.body
iron rusts when in presence of:
- water and oxygen
- sodium chloride increase the speed of rusting if water and oxygen are also present

# data[].attributes.body
barrier methods:
- painting, covering it in oil or grease, covering iron with plastic or coating it with a less reactive metal can prevent rusting due to it covering the object completely, and therefore stopping air and oxygen from getting to the iron.

galvanising:
- coating the iron with a layer of zinc
- this prevents rusting by being a barrier to oxygen and water if it is not scratched
- if scratched, still no rusting occurs due to the zinc being more reactive and therefore oxygen and water will react with the zinc and not the iron.

sacrificial protection:
- a more reactive metal is used to cover the iron
- the more reactive metal will react with oxygen and water instead of the iron

# data[].attributes.body
- Oxidation: gain of oxygen or loss of electrons
- Reduction: loss of oxygen or gaining of electrons
- Redox: reduction and oxidation occurs
- Oxidising Agent: oxidises something by taking away electrons
- Reducing Agent: reduces something by giving electrons

# data[].attributes.body
- add acid into a conical flask
- add metal into the conical flask
- observe the reactions and the rate in which bubbles are produced
magnesium:
- quick reaction
- bubbles of gas
- magnesium disappears
- colourless solution formed
- HCl: Mg + 2HCl --> MgCl2 + H2
- H2SO4: Mg + H2SO4 --> MgSO4 + H2
zinc:
- slower reaction than magnesium
- bubbles of gas
- zinc disappears
- colourless solution forms
- HCl: Zn + 2HCl --> ZnCl2 + H2
- H2SO4: Zn + H2SO4 --> ZnSO4 + H2
iron:
- slower reaction than zinc
- bubbles of gas
- iron disappears
- pale green solution forms
- HCl: Fe + 2HCl --> FeCl2 + H2
- H2SO4: Fe + H2SO4 --> FeSO4 + H2

# data[].attributes.body
most metals are extracted from the Earth's crust and unreactive metals are often found as the uncombined elements

# data[].attributes.body
carbon extraction for iron:
- heated by carbon
- carbon is higher in the reactivity series, hence it takes away oxygen
- a redox reaction takes place
- oxygen is removed and you get iron on its own

electrolysis for aluminium:
- at the cathode, reduction takes place due to aluminium being positively charged so it is attracted to the cathode (negative)
- at the anode, oxidation takes place
- due to this aluminium is seperated

# data[].attributes.body
carbon extraction:
- used to extract metals below carbon in the reactivity series
- extracted by heating with with a reducing agent like carbon or carbon monoxide in a blast furnace

electrolysis:
- used to extract metals above carbon in the reactivity series
- extracted by electrolysis of the molten chloride or molten oxide

# data[].attributes.body
aluminium:
- isn't very strong on its own so often aluminium alloys are used instead
- used for planes, electricity cables, pots and pans
- conducts electricity, heat and it resists corrosion due to being very thing, strong and due to its aluminium oxide surface

copper:
- used for electrical wires, pots and pans, water pipes, and surfaces in hospitals
- it is a very good conductor of electricity
- ductile
- very good conductor of heat
- unreactive
- malleable
- it does not react with hot or cold water
- has antimicrobial properties

iron:
- used for car bodies, iron nails, ships and bridges
- it is strong and can withstand collisions

steel:
mild (low carbon) steel (contains up to 0.25% carbon):
- used for car bodies, nails
- it is strong
- malleable
- ductile

high-carbon steel (iron containing about 0.6-1.2% carbon):
- usually also contains small amount of manganese
- used for cutting tools
- it is hard and strong

stainless steel (iron with chromium and often nickel):
- used for cutlery and sinks
- it is resistant to corrosion due to the chromium forming a strong oxide layer, preventing oxygen from affecting the objects.

# data[].attributes.body
- an alloy is a mixture of metal and one or more elements, usually other metals or carbon

# data[].attributes.body
alloys are harder than pure mixtures because:
- the mixture contains different sized atoms
- breaks up the regular lattice arrangement
- harder for layers of ions to slide over each other
- therefore harder and stronger than pure metals (less malleable + ductile)

# data[].attributes.body
litmus:
- red litmus stays the same besides when in contact with an alkali, which then it turns blue
- blue litmus stays the same besides when in contact with an acid, which then it turns red

phenolphthalein:
- turns pink when it comes in contact with an alkali

methyl orange:
- turns red when in contact with acids
- yellow with alkali
- orange with a neutral substance

# data[].attributes.body
- 0-3 is strongly acidic
- 4-6 is weakly acidic
- 7 is neutral
- 8-10 is weakly alkaline
- 11-14 is strongly alkaline

# data[].attributes.body
- acid: strong (red), weak (yellow/ yellow-green)
- alkali: strong (dark purple), weak (blue)
- neutral: pure green

# data[].attributes.body
- acids in an aqueous solution are a source of hydrogen ions and alkalis in an aqueous are a source of hydroxide ions

# data[].attributes.body
- alkalis can neutralise acids

# data[].attributes.body
titrations can be used to find out how much of the acid/alkali reacts with a certain volume of alkali/acid

- use either phenolphthalein or methyl orange
- use pipette to measure alkali solution into conical flask
- add drops of indicator
- add acid into burette + note starting volume
- add acid in the burette into the alkali solution continuously, swirling until indicator changes to colour indicating a neutral solution
-  note the final volume of acid in the burette
- repeat until you have three concordant results

# data[].attributes.body
- sodium, potassium and ammonium are soluble
- all nitrates are soluble
- all chlorides besides silver chlorides and lead (II) are soluble
- all sulfates except barium, calcium and lead (II) are soluble
- all carbonates besides sodium, potassium and ammonium are insoluble
- all hydroxides besides sodium, potassium and calcium are insoluble

# data[].attributes.body
Acids donate protons (H⁺)
Bases accept protons

# data[].attributes.body
Acids are proton donors as they ionize in solution producing protons, H+ ions; these H+ ions make the aqueous solution acidic.
Bases(alkalis) are proton acceptors as they ionize in solution producing OH- ions which can accept protons; These OH⁻ ions make the aqueous solution alkaline.

# data[].attributes.body
Only metals above hydrogen in the reactivity series will react with dilute acids. Acids will react with metals to form a salt and hydrogen gas:
Acid    +    Metal   →    Salt    +    Hydrogen

All metal oxides, metal hydroxides can act as bases. When they react with acid,  a neutralisation reaction occurs. Acids and bases will react to produce a salt and water:
Acid    +    Base   →    Salt    +    Water

Acids will react with metal carbonates to form salts, carbon dioxide and water:
Acid    +    Metal Carbonate   →    Salt    +    Carbon Dioxide    +    Water

# data[].attributes.body
Alkali: Bases that are soluble in water and dissolves to form hydroxide ions OH-

Metal Oxides can act as a base and is soluble in water
Metal Oxide    +    Acid   →    Salt    +    Water

Metal Hydroxides can act as a base and is soluble in water
Metal Hydroxide    +    Acid   →    Salt    +    Water

Ammonia can act as a base and is soluble in water

Ammonia    +    Acid   →  (Ammonium)  Salt    +    Water

# data[].attributes.body
Preparation of  Soluble Salts
an experiment to prepare a pure, dry sample of a soluble salt, starting from an insoluble reactant
Using Dilute Acid and Insoluble Base:
Method:

Add dilute acid into a beaker and heat using a bunsen burner flame

Add the insoluble base, a little at a time, to the warm dilute acid and stir until the base is in excess (i.e. until the base stops disappearing and a suspension of the base forms in the acid)

Filter the mixture into an evaporating basin to remove the excess base

Heat the solution to evaporate water and to make the solution saturated. Check the solution is saturated by dipping a cold, glass rod to the solution and seeing if crystals form on the end.

Leave the filtrate in a warm place to dry and crystallise

Decant excess solution

Blot crystals dry

# data[].attributes.body
Preparation of  Soluble Salts
an experiment to prepare a pure, dry sample of a soluble salt, starting from an Acid and Alkali
Using Dilute Acid and Alkali:
Method:

Use pipette to measure alkali into conical flask and add a few drops of indicator (phenolphthalein or methyl orange)

Add acid into burette and note the starting volume

Add acid in burette into alkali in flask until indicator changes to appropriate colour

Note and record the final volume of acid in burette and calculate the volume of acid added (starting volume of acid – final volume of acid)

Add this same volume of acid into the same volume of alkali without the indicator

Heat to partially evaporate to leave a saturated solution

Leave to crystallise

Excess solution is decanted and crystals are blot dry

# data[].attributes.body
Preparation of Insoluble Salts

experiment to prepare a pure, dry sample of an insoluble salt, starting from two soluble reactants
Using Two Soluble Reactants:

An insoluble salt can be made by a precipitation reaction by mixing two soluble salt solutions

A precipitation reaction is a reaction that produces a precipitate

Method:

Dissolve soluble salts in water and mix together using a stirring rod in a beaker

Filter to remove precipitate from mixture

Wash filtrate with water to remove traces of other solutions

Leave in an oven to dry

# data[].attributes.body
Preparation of Pure, Dry Hydrated Copper (II) Sulfate Crystals
Practical: Prepare a sample of pure, dry hydrated Copper (II) Sulfate Crystals starting from Copper (II) Oxide

Acid = Dilute Sulfuric Acid
Insoluble Base = Copper (II) Oxide

Method:

Add dilute sulfuric acid into a beaker and heat using a bunsen burner flame

Add copper (II) oxide (insoluble base), a little at a time to the warm dilute sulfuric acid and stir until the copper (II) oxide is in excess (stops disappearing)

Filter the mixture into an evaporating basin to remove the excess copper (II) oxide

Leave the filtrate in a warm place to dry and crystallize

Decant excess solution

Blot crystals dry

Equation Of Reaction:

Copper (II) Oxide    +    Dilute Sulfuric Acid   →   Copper (II) Sulphate    +    Water              CuO (s)                             H ₂ SO ₄ (aq)                        CuSO ₄ (s)                 H ₂ O (l)

# data[].attributes.body
Preparation Of Pure, Dry Lead (II) Sulfate Crystals
Practical: Prepare a sample of pure, dry Lead (II) Sulfate

Soluble Salt 1 = Lead (II) Nitrate
Soluble Salt 2 = Potassium Sulfate

Method:

Dissolve Lead (II) Nitrate and Potassium Sulfate in water and mix together using a stirring rod in a beaker

Filter to remove precipitate from mixture

Wash residue with water to remove traces of potassium nitrate solution

Leave in an oven to dry

Equation of Reaction:

Lead (II) Nitrate  +  Potassium Sulfate  →  Lead (II) Sulfate  +   Potassium Nitrate        Pb(NO ₃)₂  (s)               K ₂ SO ₄ (s)                      PbSO ₄ (s)                  KNO ₃ (s)

# data[].attributes.body
Test for Hydrogen

Method:

Collect gas into a boiling tube

Put lit splint inside

Result:

Burns with a ‘Squeaky Pop’ if hydrogen is present

Equation:

2H₂ (g)    +    O₂ (g)     →     2H₂O (l)

Test for Oxygen
Method:

Collect gas into a boiling tube

Insert glowing splint

Result:

Splint relights if oxygen is present

Test for Carbon Dioxide

Method:

Bubble gas through limewater

Observe colour change

Result:

Limewater turns milky and cloudy if carbon dioxide is present

Equation:

Ca(OH)₂ (aq)    +    CO₂ (g)     →     CaCO₃ (s)     +    H₂O (l)

*The white solid, CaCO₃, turns the limewater milky

Test for Ammonia

Method:

Lower damp red litmus paper or damp universal indicator (pH) paper into test solution

Result:

Damp red litmus paper turns blue if Ammonia is present

Damp universal indicator (pH) paper turns purple if Ammonia is present

Equation:

NH₃ (g)    +    H₂O (l)     →     NH⁴⁺ (aq)     +    OH– (aq)

*The Hydroxide Ions, OH–, turns the Litmus Blue

Test for Chlorine

Method:

Lower damp litmus paper or moist starch-iodide paper into test solution

Result:

Damp litmus paper is bleached white if chlorine is present

Moist starch-iodide paper turns blue if chlorine is present

Equation for moist starch-iodide Paper:

Cl₂ (g)    +    2l– (aq)     →     2Cl– (aq)     +    I₂ (aq)

*The iodine formed turns the starch blue

# data[].attributes.body
Flame Tests - used to identify the metal cations by the colour of the flame they produce

Method:

Clean platinum or nichrome wire by dipping it into hydrochloric acid then placing it in the roaring flame (this is repeated until the wire no longer produces a colour in the flame).

The end of the wire is dipped into fresh hydrochloric acid and then into the solid sample under test.

The end of the wire should then be placed into a non-roaring, non-luminous Bunsen flame.

Colour of flame is observed and recorded.

# data[].attributes.body
The colours formed in flame tests for these cations:

Li⁺ is red

Na⁺ is yellow

K⁺ is lilac

Ca²⁺ is orange-red

Cu²⁺ is blue-green.

# data[].attributes.body
Test for Ammonium Ion NH ₄⁺

Method:

Add aqueous sodium hydroxide to the solid or solution and heat

Lower damp red litmus paper into gas produced

Result:

If ammonium ions are present then a pungent-smelling gas is produced

The gas produced turns damp red litmus paper blue

The gas in ammonia evolved from ammonium ions reacting with hydroxide ions from the sodium hydroxide (see below).

Equation:

NH₄⁺ (aq)             +               OH-            →                    NH₃          +         H₂O Ammonium Ions               Hydroxide Ions

Test for Cu ²⁺, Fe ²⁺ and Fe ³⁺

Method:

Add aqueous sodium hydroxide

Colour of precipitate is observed and recorded

Result and Equation:

Copper(II) produces a blue precipitate

Cu2+    +   2OH-    →    Cu(OH)₂

Iron(II) produces a green precipitate

Fe2+    +   2OH-    →    Fe(OH)₂

Iron(III) produces a brown precipitate

Fe3+    +   3OH-    →    Fe(OH)3

# data[].attributes.body
Test for Cl–, Br– and I–

Method:

Add some dilute Nitric Acid to react and remove carbonate ions

Add a few drops of Silver Nitrate solution

Colour of precipitate is observed and recorded

Precipitate is silver halide compound

Result and Equation:

Chloride gives a white precipitate

Ag+    +   Cl-    →    AgCl

Bromide gives a cream precipitate

Ag+    +   Br-    →    AgBr

Iodine gives a yellow precipitate

Ag+    +   I-    →    AgI

Test for SO ₄ ²⁻

Method:

Add some dilute Hydrochloric Acid to react and remove carbonate ions

Add a few drops of Barium Chloride solution

Colour of precipitate is observed and recorded

Result:

If sulfate ions are present, a white precipitate will form (Barium Sulfate)

Equation:

Ba²⁺ (aq)      +         SO₄ ²⁻  (aq)       →         BaSO₄ (s)

Test for CO ₃ ²⁻

Method:

Add dilute Hydrochloric Acid

Bubble the gas produced into limewater

Colour of precipitate is observed and recorded

Result:

If carbonate ions are present, carbon dioxide is produced when reacted with hydrochloric acid.

Carbon dioxide reacts with limewater to turn milky.

Equation:

CO₃ ²⁻ (aq)      +         2H⁺  (aq)      →       CO₂ (g)       +       H₂O  (l)

# data[].attributes.body
Chemical Test for Water
Method:

Add liquid to anhydrous copper (II) sulfate

Colour change is observed and recorded

Result:

If liquid is water, the white powder will turn blue

This is because hydrated copper (II) sulfate is formed and is a blue crystal

Does not indicate whether water is pure

Equation:

CuSO₄ (s)      +         5H₂O  (l)      →         CuSO₄.5H₂O (s)
White                                                                   Blue

# data[].attributes.body
Physical Test for Pure Water

Method:

Boil the liquid and measure temperature as liquid starts to boil – its boiling point

Freeze the liquid to measure its freezing point (same as melting point)

Result:

Boiling point of pure water is 100°C

Freezing point (melting point) of water is 0°C

If either are increased or decreased water sample contains impurities