Chemical Kinetics Thermodynamics – does a reaction take place? Kinetics – how does a reaction proceed (reaction mechanism) and how fast (reaction rate). Reaction rate is the change in the concentration of a reactant or a product with time (Units: mol/Ls). R P rate = - D[R] Dt D[R] = change in [reactants] over a time period Dt rate = D[P] Dt D[P] = change in [products] over a time period Dt Because [R] decreases with time, D[R] is negative.
A B time rate = - D[A] Dt rate = D[B] Dt
Br2 (aq) + HCOOH (aq) 2Br- (aq) + 2H+ (aq) + CO2 (g) slope of tangent slope of tangent slope of tangent average rate = - D[Br2] Dt = - [Br2]final – [Br2]initial tfinal - tinitial instantaneous rate = rate for specific instance in time
Practice! Read p. 358-366 p. 361-366 #1-11 p. 366 #1-3ab (omit 2e)