Since the carbon14
concentration decreases with time, d[C14]/dt is a
negative number;thus a minus sign is required on the right side
of the equation. It is common to bring the minus sign to the left
side, beside the rate term, and to write the rate equation as
One reaction for which the rate law has been
established is the hydrogeniodine reaction. It depends on the concentrations
of H_{2} and I_{2}
The only unfamiliar aspect about this
rate
equation is the dx/dt style of writing rates.
This equation should be translated as: "The rate of disappearance
of H_{2} and the rate of disappearance of
I_{2}, both are half the rate of appearance
of HI (since two HI molecules are produced), and each of these is
proportional to the product of H_{2 }and
I_{2} concentrations.
