Concentration- time graphs

• zero order

  -concentration of reactant is inversely proportional to time

  -change in concentration of reactant has no effect on the rate of reaction
• zero order

  -negative gradient

  -straight down line

  -Rate = K

  
• second order

  -concentration of reactant decreases over time
• First order

  -decreasing gradient over time

  -as gradient decreases the reaction gradually slows down

  
• Second order

  -steeper curve going downwards

  
• what is half life?

  time taken for half of the reactant to be used up

  • decreases to half its original value
• zero order half life

  successive half lives decrease with time

  • less time for concentration of reactant to halve as the reaction progresses
• first order half life

  half life remains constant throughout the reaction

  • same amount of time for the concentration of the reaction to be halved as the reaction progresses
• second order half life

  half life increases with time as the reaction progresses

  • takes more time for the concentration of reactant to halve
• first order half life

  k= ln2 / t½

  t½ = half life
• half life


  concentration-time graphs

  
• for concentration- time graphs the gradient equals the rate