For a first-order reaction, the half-life is independent of the initial concentration. What is the expression for half-life?
Correct Answer: t1/2 = 0.693/k
- Step 1: Understand what a first-order reaction is. It is a type of chemical reaction where the rate depends on the concentration of one reactant.
- Step 2: Learn about half-life. Half-life is the time it takes for half of the reactant to be used up in a reaction.
- Step 3: Note that for first-order reactions, the half-life does not change with different starting amounts of reactant.
- Step 4: The formula for calculating the half-life (t1/2) of a first-order reaction is derived from the rate constant (k).
- Step 5: The expression for half-life in a first-order reaction is t1/2 = 0.693/k.
- First-Order Reactions – Reactions where the rate is directly proportional to the concentration of one reactant.
- Half-Life – The time required for the concentration of a reactant to decrease to half its initial value.
- Independence from Initial Concentration – In first-order reactions, the half-life does not depend on the initial concentration of the reactant.
