Chemical Kinetics Vocabulary Flashcards

Vocabulary flashcards covering core topics in reaction kinetics, including integrated rate laws, units of k, half-life equations, catalysts, and reaction mechanisms.

Activation Energy

Energy required to reach the transition state.

Transition State

Highest-energy point along the reaction pathway.

Successful Collision

A collision with enough energy and appropriate orientation.

Reaction Rate

Change in concentration per unit time.

Reactant Rate Sign

Negative.

Product Rate Sign

Positive.

Experimental Rate Law

$$\text{Rate} = k[A]^m[B]^n$$

Rate-Law Exponents

Exponents derived from experimental data.

Doubling a Second-Order Reactant

Makes the reaction rate $4 \times$ larger.

Units of $k$ for Zeroth-Order

$$M\,s^{-1}$$

Units of $k$ for First-Order

$$s^{-1}$$

Units of $k$ for Second-Order

$$M^{-1}\,s^{-1}$$

Zero-Order Integrated Rate Law

$$[A]_t = [A]_0 - kt$$

First-Order Integrated Rate Law

$$\ln[A]_t = -kt + \ln[A]_0$$

Second-Order Integrated Rate Law

$$\frac{1}{[A]_t} = kt + \frac{1}{[A]_0}$$

Zero-Order Linear Plot

$[A]$ vs. time.

First-Order Linear Plot

$\ln[A]$ vs. time.

Second-Order Linear Plot

$\frac{1}{[A]}$ vs. time.

First-Order Half-Life

$$t_{1/2} = \frac{\ln(2)}{k}$$

Second-Order Half-Life

$$t_{1/2} = \frac{1}{k[A]_0}$$

Zero-Order Half-Life

$$t_{1/2} = \frac{[A]_0}{2k}$$

Arrhenius Equation

$$k = A e^{-\frac{E_a}{RT}}$$

Temperature Effect on $k$

When temperature increases, $k$ increases.

Properties Changed by a Catalyst

Reaction pathway/mechanism and activation energy.

Properties Unchanged by a Catalyst

$\Delta E$, reactant/product energies, or equilibrium position.

Intermediate

Produced in one step and consumed in another.

Catalyst

Consumed in one step and regenerated in another.

Rate-Determining Step

Usually the slowest step.

Matching a Rate Law

Does not prove a mechanism; it only supports it.