C7 Flashcards
Define Bulk Chemicals and give examples
chemicals produced on a large scale
e.g ammonia, sulfuric acid, sodium hydroxide
Define fine chemicals and give examples
chemical produced on a small scale
e.g drugs, food additives and fragrances
5 stages involved in producing chemicals in industry
Preparation of feedstock synthesis separation of products monitoring the purity of product handling of by-products and waste
8 things you should consider when deciding if process is sustainable
Will raw materials run out? how good is the atom economy? what do i do with the waste? what are the energy costs? will it damage the environment? what are the health and safety risks? benefits or risks to society? profitable?
exothermic
energy is released to its surroundings, the product energy level is lower than reactants
The energy released by forming bonds is greater than the energy used to break bonds
endothermic
energy is taken from surroundings, products energy level is higher than reactants
The energy used for breaking bonds is greater than the energy released by forming bonds
catalyst and how it works
speeds up a reaction without being used,
catalysts lower the activation energy by providing alternative routes
overall energy change for reaction stays the same
what is a reversible reaction
Can go both ways
A reversible reaction is one where the products of the reaction can themselves react to the original reactants
A + B C + D
what is a dynamic equilibrium
reaction that goes both ways, the reactions are taking place at the same rate
haber process
This is an important industrial process. it produces ammonia which is needed for fertilisers
reversible reaction
non biological
N2 + 3H2 2NH3 (+heat)
nitrogen from air (78%) hydrogen from the cracking of chemicals in natural gas using steam
as its reversible not all nitrogen and hydrogen converts to ammonia
gases don’t stay in reaction vessel long enough to reach equilibrium
N2 and H2 that don’t react are recycled = yield of ammonia increases
uses high pressure to favour forward reaction and high temps for a quick reaction (but this - yield)
nitrogen fixation
NItrogen fixation is abut taking nitrogen and turning it into chemicals we can use, like in the barber process,
turns N2 from air to ammonia
Are alkanes reactive? why?
not really, the c-c and c-h bonds are hard to break
first 4 alkanes and there formulas
methane CH4, ethane C2H6, propane C3H8, butane C4H10
Methane + oxygen –>
CH4 + O2 –> (balance it)
carbon dioxide + water
CH4 + 2O2 –> CO2 + 2H2O
How these react:
sodium + ethanol reaction
sodium + water reaction
ethanol = slow reaction, few bubbles of hydrogen water = fast reaction, lots of bubbles of hydrogen
