12.3 Rate Laws

12.3 Rate Laws

• The rate of a reaction is increased by the presence of a catalyst.

• Chemical reactions occur when a molecule collides with another.
• Scientists can use simulations to predict how the parameters discussed earlier will affect the rate of a reaction.
• The temperature, concentration, and nature of the reactants affect reaction rates.

• Concentrations of reactants affect the rate of a reaction.

• We will explain how a reactant's concentration can't affect a reaction despite being involved in it.

• In a transesterification reaction, a triglyceride reacts with an alcohol.

• To use this method, we pick two sets of rate data that differ in the concentration of only one reactant and set up a ratio of the two rates and the two rate laws.
• After canceling terms that are equal, we are left with an equation that has no known coefficients of concentration.
• The equation for the coefficients is solved by us.

• Nitrogen oxides deplete ozone in the upper atmosphere.

• During the winter, the atmospheric ozone concentration has decreased.
• The map shows the concentration as purple.

• This reaction was studied in the laboratory and the rate data was determined.

• Determine the rate law and the rate constant for the reaction.

• In the last three experiments, NO varies while O3 remains the same.
• The rate triples when [NO] triples from trial 3 to 5.

• In the first three experiments, NO is constant and O varies.
• The rate increases when [O3] triples from trial 1 to 3.

• The mol/L/s is the rate of a reaction.
• The concentration units are mol3/L3.

• The coefficients in the chemical equation for the reaction are the same as the reaction orders in the rate law.
• This is often not the case.

• When a decrease in reaction rate is caused by an increase in concentration of one reactant, rate laws may show fractional orders for some reactants.