Lecture #10: Reaction Rates

This set of vocabulary flashcards covers fundamental kinetic concepts including reaction rate calculations, instantaneous rate determination, and stoichiometric relationships in rate laws based on Lecture #10.

Reaction Rate

The change in the concentration of a reactant or product per change in time, expressed as $\text{Rate} = \frac{\Delta [A]}{\Delta t}$.

[A]

The concentration of a reactant or product, measured in units of $mol/L$.

Reactant Rate Sign Convention

Since the concentration of a reactant (such as $NO_2$) decreases over time, a negative sign must be included in its rate calculation to ensure the rate value is positive.

Instantaneous Rate

The rate of a reaction at a specific point in time, determined by calculating the slope of a line tangent to the concentration-time curve at that point.

Slope

The calculated change in $y$ divided by the change in $x$; for a reactant concentration graph, the rate is expressed as $-\text{Slope}$.

General Rate Law Relationship

A formula that relates the rates of change of all reactants and products in a reaction based on their stoichiometric coefficients.

Rate Correlation for $2NO_2 \rightarrow 2NO + O_2$

The specific relationship defined as $-\frac{1}{2} \frac{\Delta [NO_2]}{\Delta t} = \frac{1}{2} \frac{\Delta [NO]}{\Delta t} = \frac{\Delta [O_2]}{\Delta t}$.

Ahmed Zewail

A scientist and researcher whose lab at Caltech is noted for its work in observing concentrations as a function of time for chemical reactions.

Reaction Decomposition of $NO_2$ at $300\,^{\circ}C$

The specific reaction ($2NO_2(g) \rightarrow 2NO(g) + O_2(g)$) documented in Table 15.1 used to show how concentration changes over time.

Reaction rate of $NO_2$ at $50\,\text{sec}$

Calculated as $-(0.0079 - 0.0100) / (50 - 0) = +4.2 \times 10^{-5}\,mol/L \cdot s$.