What is the unit of rate constant for a second-order reaction?
Practice Questions
Q1
What is the unit of rate constant for a second-order reaction?
mol/L·s
L/(mol·s)
s^-1
mol^2/L^2·s
Questions & Step-by-Step Solutions
What is the unit of rate constant for a second-order reaction?
Step 1: Understand what a second-order reaction is. A second-order reaction is one where the rate of reaction depends on the concentration of two reactants or the square of the concentration of one reactant.
Step 2: Write the general rate equation for a second-order reaction. The rate equation can be written as Rate = k[A]^2 or Rate = k[A][B], where k is the rate constant and [A] and [B] are the concentrations of the reactants.
Step 3: Identify the units of rate. The rate of a reaction is usually expressed in moles per liter per second (mol/L/s or M/s).
Step 4: Identify the units of concentration. Concentration is expressed in moles per liter (mol/L or M).
Step 5: For a second-order reaction, if we use the equation Rate = k[A]^2, we can rearrange it to find the unit of k: k = Rate / [A]^2.
Step 6: Substitute the units into the equation: k = (mol/L/s) / (mol/L)^2.
Step 7: Simplify the units: k = (mol/L/s) * (L^2/mol^2) = L/(mol·s).
Step 8: Conclude that the unit of the rate constant k for a second-order reaction is L/(mol·s).
