Ch 12 Txt

  1. chemical kinetics
    the area of chemistry concerned with reaction rates and the sequence of steps by which reactions occur
  2. To describe a reaction rate, we must specify __. What is the rate?
    • how fast the concentration of a reactant or a product changes per unit time
    • rate= concentration change/ time change
  3. reaction rate
    • either the increase in the concentration of a product per unit time or as the decresae in the concentration of a reactant per unit time 
    • rate=delta[x]/ deltat
  4. What are units for rates
    Molar per second M/s
  5. Why do we define reaction rate in terms of concentration (moles per liter) rather than moles?
    because we want the rate to be independent of the scale of the reaction
  6. The steeper the slope of the hypotenuse, the __
    faster the rate
  7. Reaction rate is defined as a __
    positive quantity
  8. The general rate of a reaciton equals
    the rate of consumption of a reactant or formation of a product divided by its coefficient in the balanced chem equation
  9. The slope of the tangent to a concentration-versus-time curve at a time t is called the __ at that particular time. The instantaneous rate at the beginning of a rate (t=0) is called the __.
    • instantaneous rate
    • initial rate
  10. what is the rate law?
    rate= - delta[A]/ deltat= k[A]^m[B]^n
  11. What does an exponent of one indicate?
    the rate depends linearly on the concentration of the corresponding reactant
  12. What does m=0 mean?
    the rate is independent of the concentration of A because any number raised to the zeroth power equals one
  13. If m is negative, __
    the rate decreases as [A] increases
  14. The values of the exponents m and n determine the __ with respect to A and B, respectively. The sum of teh exponents (m+n) defines the __.
    • reaction order
    • overall reaction order
  15. The values of the exponents in a rate law must be determined by __; they cannot be deduced from the __ of the reaction.
    • experiment
    • stoichiometry
  16. One method of determining the values of the exponents in a rate law--the __--is to carry out a series of experiments in which the initial rate of a reaction is measured as a function of different sets of initial concentrations.
    method of initial rates
  17. first order reaction
    one whose rate depends on the concentration of a single reactant raised to the first power
  18. What is the integrated rate law?
    ln[A]t/[A]0= -kt

    [A]0 is initial time concentration
  19. A graph of ln [A] versus time is a __ having a slope of __. The value of hte rate constant is simply equal  to __.
    • straight line
    • m=-k
    • -(Slope)
  20. First order reaction graphs?
    the exponential decay is the same for every interval
Card Set
Ch 12 Txt
Test TWO