Presentation on theme: "Year 12 Chemistry. Much of the work of chemists involves monitoring the reactants and products of reactions and managing reaction conditions."— Presentation transcript:
Year 12 Chemistry
Much of the work of chemists involves monitoring the reactants and products of reactions and managing reaction conditions
A variety of industries employ chemists. Some of these include: Inorganic chemical synthesis Organic chemical synthesis Petrochemical industry Pharmaceutical industry Plastics industry Mining industry Food processing Environmental analysis Chemists work with a variety of other professionals including plant managers, engineers, computer programmers and plant operators. It is essential that chemists are able to communicate with a variety of people from a different academic backgrounds
Chemists in this role assist in the production of chemicals such as: Ammonia Fertilisers Explosives Various acids Source: These chemists are concerned with quality control of final products and may be involved in the development of new products.
Chemists in this role assist in the production of chemicals such as: solvents detergents dyes pesticides herbicides Source: These chemists are concerned with quality control of final products and may be involved in the development of new products.
Chemists in this role are involved in the production of: Petrol Kerosene Natural gas LPG Oils Source: These chemists are concerned with maximum yield, quality control of final products and may be involved in the development of new products.
Chemists in this role do a variety of tasks including: Environmental reclamation Purification of minerals Extraction of metals Research Analytical testing Source:
Chemists in these roles perform a variety of duties to monitor and protect the natural environment. Some roles include: Monitoring water supplies Monitoring air quality Monitoring soil contamination Analysing effluent from industry Source: Chemists in this role use a variety of analytical techniques including wet chemical and modern instrumental analysis to monitor chemical contamination in the environment
The products from the combustion of petrol depend upon the conditions of the reaction Complete combustion (plenty of O 2 ) 2C 8 H 18 (l) + 25O 2 (g) 16CO 2 (g) + 18H 2 O (l) Incomplete combustion (insufficient O 2 ) C 8 H 18 (l) + O 2 (g) CO 2 (g) + CO (g) + C (s) + H 2 O (l) + unburnt hydrocarbons (not balanced) Note the additional products in the incomplete combustion. Extra CO is poisonous, C represents soot and unburnt hydrocarbons from exhaust pollute our cities. Poorly tuned vehicles and inefficient mufflers (loud ones!) result in these problems Source:
Chemical processes in industry require monitoring and management to maximise production
In 1912, German scientist, Fritz Haber developed a process for manufacturing ammonia from nitrogen and hydrogen. N 2 (g) + 3H 2 (g) 2NH 3 (g) + 92kJ Source: Notice that this reaction is reversible which can establish equilibrium. This means that Le Chatelier’s Principle applies to the chemistry of this process. Also, note that the forward reaction is exothermic
Source: Chemistry Contexts 2, 2006 Notice the lack of waste in this process. All unreacted gases are recycled and heat can be collected to be used in the reaction vessel Ammonia is made here
Fertilisers for plants – plants need nitrogen in the form of ammonium and nitrate salts. These are manufactured from ammonia. Metal extraction – examples are Ni and Au Cleaning agents Production a cyanide for plastics manufacturing Manufacture of synthetic materials such as nylon Manufacture of explosives Manufacture of some pharmaceuticals
N 2 (g) + 3H 2 (g) 2NH 3 (g) + 92kJ Using your knowledge of Le Chatelier’s Principle, describe what the optimum conditions (in terms of yield and rate) for this reaction will be in relation to the following: Temperature Pressure Use of a catalyst
Manufactured products, including food, drugs and household chemicals, are analysed to determine or ensure their chemical composition
Invented by an Australian, this technology is used to detect low concentrations (ppm, ppb) of metal ions in solutions. This is useful in Agriculture and Environmental monitoring. Australian, Alan Walsh invented the first working AAS in 1952
Anions Cl-, SO 4 2-, CO 3 2-, PO 4 3- Ppt tests Ag + forms insol compounds with chloride, carbonate and phosphate Ba 2+ forms insol compound with sulfate Cations Ba 2+, Ca 2+, Cu 2+, Pb 2+, Fe 2+, Fe 3+ Flame tests See p 218 in text Ppt tests HCl forms insol cpd with lead NH 3 forms insol cpd with many others (see flow chart) See exp’t 35 – “Hunt for Ions”