Introduction to Reaction Rate

Reaction Rate

The change in the amount (molar concentration) of a reactant or product per unit of time.

Rate Expression

A mathematical representation of concentration change over time, expressed as (-\frac{\Delta[A]}{\Delta t}) for reactants and (\frac{\Delta[B]}{\Delta t}) for products.

Average Rate

The rate calculated over a specific time interval ((\Delta t)), typically decreasing as the reaction proceeds.

Instantaneous Rate

The rate at a specific point in time (t), determined by the slope of the tangent to the concentration-vs-time curve.

Initial Rate

The instantaneous rate at the moment the reaction commences ((t = 0)).

Stoichiometric Coefficients

The coefficients in a balanced chemical equation that relate the relative rates of reactants and products.

Factors Affecting Reaction Rates

Chemical nature, physical state, surface area, temperature, concentration, and presence of catalysts.

Catalysts

Substances that increase the rate of a reaction without being consumed in the process.

Enzymes

Biological catalysts that speed up reactions, such as those used in glucose urinalysis test strips.

Practical Application of Reaction Rates

Used in urinalysis test strips to detect substances like glucose through kinetic reactions.

Temperature Effect on Reaction Rates

Increasing temperature raises kinetic energy, generally doubling reaction rates for every 10 °C increase.

Measuring Reaction Rates in Gases

By changes in volume or pressure.

Measuring Reaction Rates in Colored Substances

By light absorption changes.

Measuring Reaction Rates in Aqueous Electrolytes

By changes in electrical conductivity.

Measuring Reaction Rates in Solutions

By changes in molar concentration (M).