C4

Acids (and Alkalis)

• 1-4pH = Strong 
• 5-6pH = Weak  

An acid solution contains hydrogen ions, H+                                                        

An alkali solution contains hydrogen ions, OH- 

Base

An Alkali that dissolves in water

Neutralisation - Acid + Base --> Sodium Sulphate + Water

Relative Formula Mass = Relative Atomic Mass of a compound

Reactant Mass = Product Mass

Percentage Yeild =      Actual Yeild       x 100                                                                                               Predicted Yeild

Fertilisers increase crop yeild by replacing the essential elements used by previous crops.

Eutrophication 

• Fertilisers run into rivers using rain
• Concentration of nitrates and phosphate increases
• Algae use these nutrients and grow (algal bloom)
• Block sunlight from other plants causing them to die
• Bacteria feed on dead plants and use up water oxygen
• Fish die due to lack of oxygen

Percentage Mass =   total nitrogen mass in fertiliser    x100                                                                       relative formula mass of fertiliser

A fertiliser can be made by neutralisation but titration must be used for accurate measurements

Ammonia is made from nitrogen and hydrogen. The reaction is reversible

Haber Process

• High pressure - Increases %yield by pushing the molecules together
• Temperature of 450 C - increases rate of reaction, lowers %yield
• Iron catalyst - Increases rate of reaction

Compounds combine in a reactor vessel packed with Iron catalyst

 Not all compounds combine - nonreactive are recycled so they're not wasted

Ammonia is made all the time as more compounds go into the liquid and continuously removed as a liquid - continuous process

Detergent

• Substance that cleans
• Many are salts made by the neutralisation of acids with alkalis
• Hydrophilic (head) - forms bonds with and pulls grease of the fabric
• Hydrophobic (tail) - forms bonds with the oil or grease

The 'tails' stick into the grease and the 'heads' attract to the water. The 'heads' and water attraction causes the grease to gradually roll up into a ball and is pulled off the clothes. The grease balls are suspended in the water.

Dry Cleaning

Intermolecular bonds hold grease molecules together and dry-cleaning solvent together. These forces join anything together so the solvent binds to the grease, which then dissolves in the solvent.

Continuous

•  Works at full capacity  24/7
• Best for large scale manufacturing - Ammonia
• Bulk & identical

Batch

• Measured amounts & small quantities
• If contaminated only a small batch is effected
• Only when a new supply is required
• Higher labour costs as each batch has to be supervised

High costs of medicines                                                             

Strict safety laws, r&d (years?), raw materials (rare? Costly?), labour intensive

Development                                                                                         

Expensive, demand, takes time to break even, meeting legal requirements takes time

Different forms of the same carbon are called allotropes                              Graphite

• Black solid with a slippery structure due to weak forces between layers
• Strong covalent bonding within layers giving a high melting point
• De-localised electrons between layers conduct electricity       

Diamond

• very hard lustrous/colourless solid
• Strong covalent bonds giving a high melting point
• No de-localised electrons so doesn't conduct electricity

Buckminsterfullerene

• 60 carbon atoms,
• Fullerenes can be joined to make nanotubes

Nanotubes

• Cylindrical shape makes them very strong
• Conduct electricity
• Large surface area
• Can be used as
  • Semiconductors
  • Industrial catalysts - catalyst atoms are attached to the outer surface
  • Reinforcement for the graphite in tennis rackets
  • cages to trap/transport other molecules

River water contains: nitrates (fertilisers), lead compounds (pipes) and pesticides.

Un-purified water contains: dissolved salts/minerals, microbes,  insoluble materials  (clay particles/animal remains)

3 Main stages in water purification

• Sedimentation of particles - larger bits drop to the bottom
• Filtration of very fine particles- sand is used to filter out particles
• Chlorination - kills microbes

Precipitation reactions

Ion tested for             Test solution added                Result if ion is present

Sulfate                       Barium chloride                      White precipitate    

Chloride                      Silver nitrate                           White precipitate        

Bromide                       Silver nitrate                           Cream precipitate            

Iodide                          Silver nitrate                           Pale yellow precipitate