Concentration vs. Time Graphs

Front

What is a concentration vs. time graph?

Back

A concentration vs. time graph shows how the concentration of a reactant or product changes over time during a chemical reaction.

Front

Define the rate law expression.

Back

The rate law expression relates the rate of a chemical reaction to the concentration of its reactants, typically in the form: rate = k[A]^m[B]^n, where k is the rate constant, and m and n are the orders of the reaction with respect to reactants A and B.

Front

What does a second-order reaction mean?

Back

A second-order reaction means that the rate of reaction is proportional to the square of the concentration of one reactant or the product of the concentrations of two reactants.

Front

How can you determine the order of a reaction from a concentration vs. time graph?

Back

The order of a reaction can be determined by analyzing the shape of the graph: a straight line of [A] vs. time indicates zero order, a straight line of ln[A] vs. time indicates first order, and a straight line of 1/[A] vs. time indicates second order.

Front

What is the significance of the slope in a ln[A] vs. time graph?

Back

In a first-order reaction, the slope of the ln[A] vs. time graph is equal to -k, where k is the rate constant.

Front

What does the rate constant (k) represent?

Back

The rate constant (k) is a proportionality factor that relates the rate of a reaction to the concentrations of the reactants, and it is specific to a given reaction at a specific temperature.

Front

What is the relationship between half-life and the order of a reaction?

Back

For first-order reactions, the half-life is constant and independent of concentration. For second-order reactions, the half-life increases as the initial concentration decreases.

Front

What is a zero-order reaction?

Back

A zero-order reaction is one where the rate of reaction is constant and does not depend on the concentration of the reactants.

Front

How do you identify a first-order reaction from experimental data?

Back

A first-order reaction can be identified if a plot of ln[concentration] vs. time yields a straight line.

Front

What is the integrated rate law for a first-order reaction?

Back

The integrated rate law for a first-order reaction is ln[A] = -kt + ln[A]₀, where [A]₀ is the initial concentration.