Rate-concentration graphs

• Zero order (RC)

  rate doesn’t depend on the concentration of the reaction

  • rate of reaction remains constant
• zero order (RC)

  straight horizontal line

  gradient = 0

  intercept on y axis gives the rate constant

  
• zero order (RC)

  rate = k

  rate = k [A]⁰
• first order (RC)

  rate is directly proportional to the concentration of the reactant

  • rate of reaction increases by the same factor that the concentration of the reactant does
• first order (RC)

  rate constant = gradient

  rate = k[A] ¹

  
• second order (RC)

  rate is directly proportional to the square of the concentration of the reactant

  • rate of reaction increases more as the concentration of reactant increases
• Second order (RC)

  upward curve with a positive gradient

  rate = [A] ²

  
• initial rate (RC)

  found by drawing a tangent at t=0 and working out the gradient
• second order (RC)

  plot a second graph of rate against concentration squared

  • straight line though origin
  • gradient = k