15. The Rates of Chemical Reactions   Previous PageNext Page
       Experimental Rate Laws

Since the carbon-14 concentration decreases with time, d[C-14]/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 hydrogen-iodine reaction. It depends on the concentrations of H2 and I2

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 H2 and the rate of disappearance of I2, 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 H2 and I2 concentrations.


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