Rate law (equation) vocabulary
The rate law (rate equation) shows the mathematical relationship of rate to the concentration of substances upon which the rate depends. Ultimately, it gives chemists information about the detailed pathway (mechanism) for the reaction.
The overall reaction order is the sum of the exponents on its experimentally-determined rate law.
For a reaction:
aA+bB
cC+dD
the differential rate equation may have the form: rate = k[A]x[B]y
The exponents x and y must be experimentally determined.
The exponent is the power to which the concentration must be raised to calculate rate.
Exponents of 1 and 2 are common (if the exponent is 2 the concentration must be squared).
The rate constant k depends on the reaction and the temperature at which it is carried out.
aA+bB
cC+dDthe differential rate equation may have the form: rate = k[A]x[B]y
The exponents x and y must be experimentally determined.
The exponent is the power to which the concentration must be raised to calculate rate.
Exponents of 1 and 2 are common (if the exponent is 2 the concentration must be squared).
The rate constant k depends on the reaction and the temperature at which it is carried out.
The order of the reaction in a substance is given its exponent in the rate law (rate equation).
Order indicates how many A and B participate in the rate-determining (slowest) step.
The reaction having the rate law (rate equation) above is
The reaction having the rate law (rate equation) above is
x order in A
y order in B
If x is 1, then it is first order in A.
If y also is 1, it is first order in B.
y order in B
If x is 1, then it is first order in A.
If y also is 1, it is first order in B.
The overall reaction order is the sum of the exponents on its experimentally-determined rate law.
The overall reaction order for the reaction having the rate law given above would be x + y.
If both x and y are one (as above), the overall reaction order is 2.
The reaction is said to be second order.
If both x and y are one (as above), the overall reaction order is 2.
The reaction is said to be second order.