Concentration Changes Over Time - AP Chemistry

$k = A e^{-\frac{E_a}{RT}}$. Exponential relationship between rate constant and temperature.

Higher temperature increases reaction rate. More molecular collisions occur at higher temperatures.

The rate constant $k$ increases. Higher temperature provides more kinetic energy for reactions.

Units: $\text{s}^{-1}$. First-order rate constant has units of reciprocal time.

Units: $\text{M} \text{s}^{-1}$. Zero-order reactions have rate units of concentration per time.

Units: $\text{M}^{-1} \text{s}^{-1}$. Second-order rate constant has units of reciprocal concentration-time.

First-order reaction. Constant half-life indicates first-order kinetics.

Zero-order reaction. Rate independent of concentration changes.

$t_{1/2} = 1 \text{s}$. Using $t_{1/2} = \frac{\ln(2)}{k}$ formula.

Rate is directly proportional to concentration. Rate equals rate constant times concentration.

Second-order reaction. Rate proportional to concentration squared.

Analyze the shape of the plot. Different orders produce characteristic curve shapes.

Rate = $1 \text{M} \text{s}^{-1}$. Rate equals $k$ times concentration for first-order.

$t_{1/2} = \frac{1}{k[\text{A}]_0}$. Half-life inversely proportional to initial concentration.

Increases overall reaction rate. Provides faster pathway without changing equilibrium.

Rate constant $k$. Slope of reciprocal concentration vs time plot.

Represents collision frequency factor. Pre-exponential factor in Arrhenius equation.

Straight line downward. Constant rate produces linear concentration decrease.

Decreases activation energy $E_a$. Provides alternative pathway with lower energy barrier.

$[\text{A}]_t = [\text{A}]_0 - kt$. Linear decrease with time for zero-order kinetics.

Decreases exponentially. Rate proportional to remaining concentration.

First-order reaction. Constant half-life is characteristic of first-order kinetics.

Decreases more steeply than first-order. Rate proportional to concentration squared.

$t_{1/2} = \frac{[\text{A}]_0}{2k}$. Half-life depends on initial concentration for zero-order.

$\text{rate} = k[A]^m[B]^n$. Rate depends on concentrations raised to their respective orders.

Exponential decay curve. Rate proportional to concentration creates exponential decay.

Inversely proportional curve. Rate proportional to concentration squared.

$[\text{A}]_t = [\text{A}]_0 - kt$. Linear decrease with time for zero-order kinetics.

First-order reaction. Constant half-life is characteristic of first-order kinetics.