The Chemical Industry - Topic 6

• zero order reaction


  the rate of reaction doesn't change regardless of the concentration of the substance
• 1st order reactant


  the rate doubles / halves when the concentration of reactant is doubled
• 2nd order reactant


  if the concentration of reactant doubles the rate quadruples or if is halved the rate decreases by a factor of 4
• Rate equation


  Rate = k[A]^m[B]^n
• rate equation other


  rate = k(species in rate determining step)
• rate constant


  K
• Rate constant units


  moldm3
• Rate concentration graph - zero order


  flat

  
• rate concentration graph - 1st order

  
• rate concentration graph - 2nd order

  
• rate units zero order


  s-1
• rate units 1st order


  moldm-3s-1
• rate units 2nd order


  mol2dm-6s-1
• Arrhenius equation


  k=Ae^(-Ea/RT)

  A- frequency factor - frequency of collisions and their orientation

  t - kelvin
• rules of Arrhenius equation


  as Ea increases T gets smaller

  as T gets bigger K gets bigger
• Kc is ..... dependant


  temperature
• Increase in temperature


  Kc increases if more products formed

  Kc decrease if less products are formed
• experimental methods to determine Kc


  pH measurements , colorimetry , titration
• kc units


  moldm-3
• half life


  The time taken for the concentration of the reactant to reduce by half
• zero order reactions half life


  decreases as time proceeds
• 1st order reactions half life


  constant half life
• 2nd order reactions half life


  half life increases as reaction proceeds
• what is the slow step of a reaction


  the rate determining step
• If a reactant appears in the rate equation


  it must affect the rate and in RDS
• catalysts in rate equations


  can appear in rate equations - RDS
• coproduct


  a profitable by-product from a process.. traditionally considered to be waste that can be reused as raw materials in a different manufacturing process
• byproduct


  unwanted product with no profitability
• fixed costs


  Costs that do not vary with the quantity of output produced
• variable costs


  costs that vary with the quantity of output produced
• health and safety issues - gases


  explosive risk - must be stored and handled correctly
• h and safety issues - chemicals


  spills - expose public to hazardous material

  if in contact - respiratory irritate lungs

  damage to environment - S02 acid rain , aquatic life , limetone
• Haber process


  an industrial process for producing ammonia from nitrogen and hydrogen by combining them under high pressure in the present of an iron catalyst
• Oxides of Nitrogen (NOx)


  NO NO2 N20
• NO

  nitrogen oxide- insoluble , neutral , colourless gas - combustion of denitrifying bacteria
• N02


  brown soluble acidic - oxidation of no in atm
• N20


  dinitrogen monoxide - colourless slightly soluble and neutral , from denitryfying bacteria
• Test for NH4+ ions


  add NaOH and gently heat - NH3 gas produced
• reaction of NH4+ with NaOH - ionic


  NH4+ + OH- ----- NH3 + H20
• test for nitrate V ions


  add NaOH and devardas alloy ( mix of Cu Al Zn) , NH3 gas produced - damp red litmus blue , when HCL added ( hydrogen chloride) - white fumes of ammonium chloride formed