Reaction Rates

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[meshell]

The kinetics of the reaction A+B=> C were studied. It was determined that the reaction rate increased by a factor of 1/2 when the concentration of B was doubled. What is the reaction order of B?


I want to know what the right answer is and how you concluded with the answer.

a. -1
b. 0
c. 1
d. 2
e. none of the above

[kyle1990]

The order of the reaction is the exponent of a particular reactant, right?

For a first order reaction, doubling the concentration doubles the rate with respect to that reactant:

if  for instance A= 1

then doubling A to equal 2, we have

[2]¹=2  rate doubles

If it's a second order, then the rate quadruples if A is doubled

[2]²=4 rate quadruples

So if the concentration is doubled and the rate increases by a factor of 1/2, then:

[2]^x = .5

x= -1

Since x is negative, this implies that increasing the concentration of this reactant slows the rate of the reaction, which is an inhibitor-the exact opposite of a catalyst.