Q. What is meant by rate of reaction?
The change in concentration of reactants over time.
Q. How does concentration affect rate of reaction?
Increasing the concentration increases the number of molecules per unit volume. This leads to more frequent collisions and a greater frequency of successful collision, increasing the rate of reaction.
Q. What is linked by the rate constant?
Rate of reaction and the concentrations of the reactants raised to their orders in the rate equation.
Q. How is the order of reaction used in the rate equation? What is meant by overall order?
The order with respect to a reactant is the power to which the concentration of that reactant is raised to in the rate equation. Overall order = sum of the orders of each reactant in an equation.
Q. What is meant by the half-life of a reaction?
The average time taken for the concentration of the reactant to decrease by half.
Q. How do you calculate half-life from a first order concentration-time graph?
Using the graph, find the time taken for the concentration to half. Then find the time taken for it to half again. Calculate average of these values.
Q. What is the rate-determining step?
The slowest step of the reaction. Only species that take part in the rate-determining step affect the rate.
Q. What is the relation between the rate-determining step and the rate equation?
The species present in the rate equation are those that take part in the rate-determining step. For any reactant in the rate equation, the order attached to it tells you how many molecules of it are involved in the rate-determining step.
Q. How can the order of a reactant be predicted using a reaction mechanism?
Identify the rate-determining step, then observe how many molecules of each reactant react in the rate-determining step.
Q. How does the rate constant vary with increasing temperature?
As temperature increases, more particles with energy above the activation energy collide successfully so rate of reaction increases. It causes an increase in k.
Q. What is catalysis?
The increase in the rate of a chemical reaction due to the addition of a catalyst.
Q. What is a homogeneous catalyst?
A catalyst that is in the same state as the reactants.
Q. What is a heterogeneous catalyst?
A catalyst that is in a different state to the reactants.
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