1 Answer
The zero-order rate law describes a situation in a chemical reaction where the rate of the reaction is independent of the concentration of the reactant(s). In other words, no matter how much of the reactant is present, the rate of the reaction remains constant.
Mathematically, a zero-order reaction can be represented as:
\[
\text{Rate} = k
\]
Where:
Important points about zero-order reactions:
The integrated form of the zero-order rate law is:
\[
[A] = [A]_0 - kt
\]
Where:
Key Characteristics:
\[
t_{1/2} = \frac{[A]_0}{2k}
\]
Example:
For a zero-order reaction:
\[
\text{A} \rightarrow \text{B}
\]
If the initial concentration of A is 1 M, and the rate constant \(k\) is 0.1 M/s, then after 5 seconds, the concentration of A would decrease by \(0.1 \times 5 = 0.5 \, \text{M}\), leaving a concentration of 0.5 M.
Zero-order reactions often occur in certain conditions, like when a catalyst is involved or when the reactant is present in excess.
Mathematically, a zero-order reaction can be represented as:
\[
\text{Rate} = k
\]
Where:
- Rate is the rate of the reaction.
- k is the rate constant (which has units of concentration/time, like M/s for a reaction happening in molarity and seconds).
Important points about zero-order reactions:
- The rate of reaction does not change even if the concentration of the reactant changes.
- The concentration of the reactant decreases linearly over time because the rate is constant.
The integrated form of the zero-order rate law is:
\[
[A] = [A]_0 - kt
\]
Where:
- \([A]\) is the concentration of the reactant at time \(t\).
- \([A]_0\) is the initial concentration of the reactant.
- \(k\) is the rate constant.
- \(t\) is time.
Key Characteristics:
- In a zero-order reaction, the concentration of the reactant decreases linearly over time.
- The half-life (\(t_{1/2}\)) for a zero-order reaction depends on the initial concentration of the reactant and is given by:
\[
t_{1/2} = \frac{[A]_0}{2k}
\]
Example:
For a zero-order reaction: \[
\text{A} \rightarrow \text{B}
\]
If the initial concentration of A is 1 M, and the rate constant \(k\) is 0.1 M/s, then after 5 seconds, the concentration of A would decrease by \(0.1 \times 5 = 0.5 \, \text{M}\), leaving a concentration of 0.5 M.
Zero-order reactions often occur in certain conditions, like when a catalyst is involved or when the reactant is present in excess.