C5

Reactivity series from least reactive to most

gold, silver, copper, hydrogen, iron, zinc, carbon, aluminium, magnesium, calcium, lithium, sodium, potassium

What are the 2 non metals in the reactivity series?

hydrogen and carbon

Why does reactivity increase?

As an element has more shells, the distance between the electron on the outermost shell is further. This means the nucleus gets weaker as distance increases and there is more shielding. This means there is a higher tendency to lose electrons and means it is more reactive

neutralisation reaction 1 (with acid)

metal + acid --> salt + hydrogen

what is ore?

rock containing enough metal to be economically worth extracting

Disadvantages of extracting metals from the ground? 3/4

Destruction of habitat, noise and dust pollution, large amounts of waste leading to landfill

Benefits/disadvantages of copper extraction

Valuable metal for us but remaining ore sites are low grade ore sites which are more expensive to extract metals from

What is bioleaching?

flooding ore sites with bacteria that leaches copper from the ground to produce leachate solution.

Method for bioleaching

1. Bacteria are used in channels in the ground 2. The leach the metal ions from the ground to produce a leachate solution 3. Metals are extracted from the solution by displacement or electrolysis

Describe phytomining

uses plants to extract metals

Method for phytomining

1. Plants planted 2. They grow and take up metal ions in roots 3. Plants cut down and burned into ash 4. Ash dissolved to make a solution of the metal compound 5. Metals then extracted by displacement using scrap iron or electrolysis

Where is metal extracted from in bioleaching?

waste from quarrying

Where is metal extracted from in phytomining?

contaminated ground

Speed of process of bioleaching

very slow

Speed of process of phytomining

slow, made more efficient using quick-growing plants

Pollution from bioleaching

produce a solution of toxic chemicals which may run off into rivers, takes a long time to stop the process if river pollution occurs

Pollution from phytomining?

Involves combustion of plants but decontaminates polluted ground '

Ways to extract the copper from the solution of copper compounds

Scrap iron can be used to displace copper and other metals less reactive than it, very pure copper can be obtained by electrolysis

Is the displacement reaction endo or exo?

Exothermic

What happens when acid particles are dissolved in water?

acid particles dissociate into ions when dissolved in water

What is a strong acid + e.g. dissociation

an acid that fully dissociates in a solution - all bonds are broken/all separates e.g. HCl

What is a weak acid + e.g.s dissocation

an acid that only partially dissociates in a solution - some will maintain bonds e.g. vinegar and ethanoic acid

What is acid concentration?

mass of acid particles dissolved in every 1000 cm3

What is acid strength?

how many acid particles dissociate to release H+ ions

What does increasing mass of acid particles mean?

Increases the concentration of the solution

How much does each increment increase by on the pH scale?

Increments by x10 concentration of H+ ion

How to compare pHs - H+ concentration

1. Start at higher pH

2. Each pH drop - H+ concentration increases by x10

3. 10^n, n = how many pH jumps/pH difference

4. In terms of hydrogen ion (H+ ion) - magnitude - 10^n

Example comparison sentence of magnitudes = pH2 and pH5

magnitude of pH2 has 10^3 higher H+ ion concentration than pH5

What does universal indicator do and how?

Classifies substances: acidic, alkali, neutral and colour shows pH

How can a pH probe improve an experiment?

Gives a more accurate pH value - can improve a practical to be more accurate

Problems using universal indicator

Less accurate, Colours very similar for different pHs - hard to identify the exact colour to determine pH, Only getting whole numbers, not decimals, Different judgements from different people

Neutralisation reaction 2 (alkali)

acid + alkali --> salt + water

chemical symbol of acid+alkali reaction

H+ + OH− --> H2O

What are acids - ions definition

substances that produce H+ (aq) ions when added to water

What are alkalis - ions definition

substances that produce OH− (aq) ions when added to water

chemical symbol of sulfuric acid

H2SO4

Chemical symbol of nitric acid

HNO3

chemical symbol of hydrochloric acid

HCl

Independent variable in titration practical

concentration of sodium hydroxide

Dependent variable of titration variable

volume of acid used to neutralise concentration of sodium hydroxide

Control variable of titration practical

volume of conc. Of NaOH,

Conclusion of titration practical

As the concentration of sodium hydroxide increases, the more acid used to neutralise is needed

Titration practical metod

1. Measure 10 ml NaOH into conical flask using measuring cylinder and pipette 2. Add 5 drops of methyl orange to the conical flask 3. Titrate against HCl until colour change (yellow/orange --> permanent pink) seen - note titre 4. Repeat x3

Required practical word equation

metal oxide + acid --> salt + water

Required practical method - metal oxide

1. Add 20ml sulfuric acid to beaker and add 1 spatula of copper oxide. Stir while heating using a liquid flame over bunsen. If all CuO dissolves, add more in half spatula amounts (so it's in excess)

DO NOT LET ACID BOIL

2. Once CuO is in excess allow to cool and filter

3. Add filtrate to evaporating basin and heat over liquid flame to evaporate half amount of water or until crystals start to form

4. Allow basin to cool, label and leave by window sill

neutralisation reaction 3 _ metal carbonates

metal carbonate (s) + acid (aq) --> salt + carbon dioxide + water

What does limewater do?

Used to test presence of carbon dioxide