Practice: Given the following chemical reaction, A → B. If the concentration of A is doubled the rate increases by a factor of 2.83, what is the order of the reaction with respect to A.
Rate Law represents an equation for a chemical reaction that connects the reaction rate with the concentrations or pressures of the reactants and the rate constant.
Understanding Rate Law
Concept #1: Rate Law
Example #1: The chemical reaction: 2 A + 3 B + C → D has a Rate Law of k[A]3[B][C]0. By what factor would the rate increase if the concentration of A were tripled, the concentration of B was cut by half, the concentration of C increased by half, and the rate constant k was kept constant?
Concept #2: Rate Constant Units
Example #2: What is the overall order and the units for the rate constant k for the following chemical reaction shown below that has Rate = k [NO2]2[Cl2]?
NO2 (g) + Cl2 (g) → NOCl (g) + ClO (g)
Concept #3: Rate Law Determination
Example #3: The initial rates of reaction for 2 NO (g) + Cl2 (g) → 2 NOCl (g) are:
Experiment [NO], M [Cl2], M Initial Rate, M/s
1 0.0250 0.0510 18.2
2 0.0250 0.0255 9.08
3 0.0500 0.0255 18.2
Determine the new rate if given new initial concentrations of [NO] = 0.0730 M and [Cl2] = 0.0510 M.
Practice: The data below were collected for the following reaction: CH3Cl (g) + 3 Cl2 (g) → CCl4 (g) + 3 HCl (g)
Calculate the value and units for the rate constant k.
A. 1.25 M–0.5•s–1
B. 5.6 M–1•s–1
C. 25 M–3/2•s–1
D. 7.9 M–5/2•s–1
