First-order reactions are chemical processes where the rate is directly proportional to the concentration of one reactant. These reactions often involve the transformation of a single molecule and are characterized by a rate law expressed as rate = k[A], where 'k' is the rate constant. The text delves into examples like the decomposition of hydrogen peroxide and radioactive decay, the calculation of rate constant units, and the use of graphical analysis to determine kinetics. It also explains the concept of half-life, a crucial aspect of first-order reactions used in applications like radiometric dating.
Show More
First-order reactions have a rate that is directly proportional to the concentration of one reactant
Transformation of a single molecule into one or more products
Unimolecular first-order reactions involve the transformation of a single molecule into one or more products
The rate law for a first-order reaction is given by the equation rate = k[A], where 'k' is the rate constant and '[A]' is the concentration of the reactant
Reaction order describes how the rate of a reaction depends on the concentration of its reactants
Experimentally observing how the rate responds to changes in reactant concentration
The reaction order is determined by experimentally observing how the rate responds to changes in reactant concentration
Certain decomposition reactions, such as the conversion of hydrogen peroxide into water and oxygen, follow first-order kinetics
The decay of radioactive isotopes is an example of a first-order reaction
The presence of additional substances, like solvents, does not necessarily change the reaction order if their concentration remains constant
The rate constant for first-order reactions is expressed in units of s^-1
The concentration of reactants in a first-order reaction decreases exponentially over time
Graphical methods can be used to determine the rate constant and confirm the reaction order
The half-life of a first-order reaction is the time required for the concentration of the reactant to decrease by half, and is constant regardless of the initial concentration
00
Characteristic of first-order reaction rate
Rate directly proportional to one reactant's concentration
01
Typical molecularity of first-order reactions
Unimolecular, involving a single molecule's transformation
02
First-order reaction rate law expression
Rate = k[A], where 'k' is rate constant, '[A]' is reactant concentration
