Students can go through AP Inter 2nd Year Chemistry Notes 3rd Lesson Electrochemistry and Chemical Kinetics will help students in revising the entire concepts quickly.
AP Inter 2nd Year Chemistry Notes 3rd Lesson Electrochemistry and Chemical Kinetics
Electrochemistry
→ Galvanic cell: A device which converts chemical energy into electrical energy by the use of spontaneous redox reaction is called Galvanic cell (or) voltaic cell.
Eg.: Daniell cell.
→ The electrode whose potential is known as standard electrode (or) standard hydrogen electrode.
To determine the potential of a single electrode experimentally it combine with standard hydrogen electrode and the EMF of cell so constructed is measured with potentiometer.
→ Nernst equation is E = E + \(\frac{\mathrm{RT}}{\mathrm{nF}}\) ln[Mn+].
→ Molar conductivity: The conductivity of a volume of solution containing one gram molecular weight of the electrolyte placed between two parallel electrodes separated by a distance of unit length of 1 me(er is called molar conductivity (∧m).
→ Kohlrausch’s law of independent migration of ions: The limiting molar conductivity of an electrolytes can be represented as the sum of the individual contributions of the anion and the cation of the electrolytes.
\(\lambda_{\mathrm{m}(\mathrm{AB})}^0=\lambda_{\mathrm{A}^{+}}^0+\lambda_{\mathrm{B}^{-}}^0\)
→ The amount of chemical reaction which occurs at any electrode during electrolysis is proportional to the quantity of current passing through the electrolyte.
(Or)
The mass of the substance deposited at an electrode during the electrolysis of electrolyte is directly proportional to quantity of electricity passed through it.
→ The amounts of different substances liberated when the same quantity of electricity is passed through the electrolytic solution are proportional to their chemical equivalent weights.
m ∝ E
→ The batteries which after their use over a period of time, becomes dead and the cell reaction is completed and this cannot be reused again are called primary batteries.
Eg.: Leclanche cell, dry cell.
→ Secondary battery : A secondary battery is the battery in which after it’s use can be recharged and can be used again.
→ A fuel cell is a galvanic cell in which the chemical energy, of fuel-oxidant system is converted directly into electrical energy.
→ Metallic corrosion : The natural tendency of conversion of a metal into its mineral compound form on interaction with the environment is known as metallic corrosion.
Chemical Kinetics
→ The change in the concentration of a reactant (or) product in unit time is called speed or rate of a reaction.
(or)
The decrease in the concentration of a reactant (or) increase in the concentration of product per unit time.
→ The equation that describes mathematically the dependence of the rate of a reaction on the concentration terms of the reactants is known as the rate equation (or) rate law.
→ Order of a reaction : The sum of the powers of the concentration terms of the reactants present in the rate equation is called order of a reaction.
→ The number of reacting species (atoms, ions or molecules) taking part in an elementary reaction, which must colloid simultaneously to bring about a chemical reation is called molecularity of a reaction.
→ Examples for zero order reactions
→ [R] = Concentration of reactant after time t’ [R]0 = Initial concentrations of reactant
∴ K = \(\frac{2.303}{t} \log \frac{[R]_0}{[R]}\)
This is the integrated Equation for a first order reaction.
→ The following are the examples for gaseous first order reactions
N2O5(g) → N2O4(g) + \(\frac{1}{2}\)O2(g); SO2Cl2(g) + Cl2(g)
→ The time required for the initial concentration of the reactants to become half of it’s value during the progress of the reaction is called half life (t1/2) of reaction.
Eg: The radio active of C-14 is exponential with a half life of 5730 years.
→ Activation Energy: The energy required to for an intermediate called activated complex (c) during a chemical reaction is called activation energy.
→ The number of collisions per second per unit volume of the reaction mixture is called collisium frequency (z) for a bi molecular Elementary reactions.
→ Most of the chemical reations are accelerated by increase of temperature.