The Chemical Industry

• $rate =$$[A]^m[B]^n$

  A = reactant

  B = reactant

  m and n = order of reaction
• total order = m+n
• The rate constant (k) is constant when the temperature is constant and constant even when concentrations change
• Rate concentration graphs:

  • zero order = horizontal line (rate = k)
  • first order = conc and rate are directly proportional / (rate = k[A])
  • second order = rate is proportional to conc squared. (rate = k[A]^2)
• Concentration time graphs:

  • zero order = linear \
  • first order = curved graph
  • second order = curved graph with a kink
• Doubling concentrations would affect initial rates:

  • zero order = no change
  • first order = rate doubles
  • second order = rate quadruples
• Half life is the time taken for the initial concentration of the reactants to decrease by a half which can be found on a concentration-time graph
• If half life is constant the reaction is first order
• Rate experiments:

  • change in reactant or product mass overtime
  • change in concentration overtime
  • change in pH overtime
  • volume of gas produced overtime
• The rate dtermining step is the slowest step of the reaction and the rate equation contains all species involved in rate determining step
• The powers in the rate equation are the number of molecules of each substance involved in the rate determining step
• Kc is not affected by concentration or pressure change and the use of a catalyst as that affects the rate of reaction not the equilibrium
• Kc is affected by temperature as it changes the position of the equilibrium resulting in different concentrations of reactants and products
• Kc:

  • exothermic = decreases Kc as equilibrium shifts left
  • endothermic - increases Kc as equilibrium shift right
• Nitrogen has low reactivity due to its triple covalent bond and as they are non-polar electrophiles and nucleophiles are not attracted to the molecules
• Ammonia is NH3 and has one lone pair of electrons so it's a nucleophile
• Ammonium ions have 1 dative covalent bond of hydrogen so a 1+ charge and are often produced in acid-base reactions
• Nitrogen oxides:

  • N2O = nitrous oxide, sweet-smelling colourless gas
  • NO = nitric oxide, colourless gas
  • NO2 = nitrogen dioxide, brown gas
• Test for nitrate (V) ions is warm with devadra's alloy and NaOH and test with damp red litmus paper that should turn blu
• Test for ammonium ions is warm with NaOH and if damp red litmus turns blue then it's present
• Test for ammonia is damp red litmus paper turns blue