Chemistry Kinetics Review

Average Rate of Reaction

Change in concentration over a time interval

Determined by the slope of a secant line on the graph

Instantaneous Rate of Reaction

Rate at a specific point in time

Determined by the slope of a tangent to the curve

Indicators of Concentration Change

Aqueous ions: change in conductivity or pH

Coloured entities: change in colour intensity using spectrophotometer

Graphing Concentration vs. Time

Reaction rates are not constant, curves are steepest at start

Graph A: negative slope (decrease in reactant A)

Graph B: positive slope (increase in product B)

Rate Laws

Mathematical relationship between reactant concentration and reaction rate

Types of rate laws:

3. Differential Rate Law: relationship between initial concentration and rate
4. Integrated Rate Law: relationship between reactant concentration and time

Reaction Rate Measurement

Measured in ext{mol/L/s}

Negative sign for consumed reactants; rates of all reactants/products can be derived from known rate

Quantitative Reaction Rate

Concentration changes as reactants are consumed and products formed

Graph: negative slope for reactants, positive slope for products

Rate relationships are based on stoichiometry of the reaction

Rates vary by stoichiometric coefficients.