C6 - Introducing Chemical Synthesis

CHEMICAL SYNTHESIS 

FOOD ADDITIVES - The Chemical industry produces additives (preservatives), colourings and flavourings for food producers

CLEANING/DECORATING PRODUCTS - Products like paints contain loads of different pigments and dyes and products like bleach, oven cleaner etc have all been developed by chemists

DRUGS - Apart of the pharmaceutical industry

FERTILISERS - Contain lots of ammonia which has to be produced by the Chemical industry

Chemists have to also figure out how to make chemicals in the way that produces the highest yield   (they do this by controlling the rate of reaction) 

They must also think about the environment by choosing processes with a low impact

Some chemicals are produced on a larger scale than other (bulk code). An example of this is Sulfuric Acid which is used for lots of things such as car batteries and fertilisers - these products are LESS PURE

Other chemicals need to be made on a , 'fine scale' - ususally drugs/perfumes 

ACIDS AND ALKALIS

"Indicators contain a dye that changes colour depending on whether it's above or below a certain pH"

LITMUS PAPER is an easy way to find out if a solution is acidic or alkaline - turns red if the soluition is acid and blue if its alkaline

"pH meters can also be used to measure the pH of a substance. They consist of PROBE which is dipped into the substance, and a meter, which gives a reading of the pH"

pH METERS ARE MORE ACCURATE THAN INDICATORS

An ACID is a substance with a pH of less than 7 (they produces aqueous hydrogen ions H+ (aq) in water)

An ALKALI is a substance with a pH of greater than 7 (they produce aqueous hydroxide ions, OH- (aq) in water)

An acid and an alkali react together to form a salt and water. The products of the recation aren't acidic or alkaline - they're NEUTRAL (A neutralisatuon reaction)

Acid + Alkali                    Salt + Water

Neutralisation can also be seen in terms of H+ and OH- ions. The hydrogen ions from the acid react with the hydroxide ions from the alkali to make water (which is neutral)

H+ (aq) +  OH- (aq)                 H20 (I)