Chemistry: Raoult's Law and Henry's Law

Raoult's Law and Henry's Law

• Raoult's law states that the relative lowering of vapour pressure of a dilute solution containing a non-volatile solute is equal to the mole fraction of the solute.
• Henry's law states that the partial pressure of the gas in the vapour phase is directly proportional to the mole fraction of the gas in the solution, mathematically represented as p = KHx.

Osmotic Pressure and Isotonic Solutions

• Osmotic pressure is the extra pressure applied on a solution to prevent osmosis.
• Isotonic solutions have the same osmotic pressure at a given temperature, and a common example is blood being isotonic with saline (0.9% w/v of NaCl).

Colligative Properties

• Colligative properties are properties of dilute solutions that depend on the number of solute particles present in the solution, examples include relative lowering of vapour pressure, osmotic pressure, elevation of boiling point, and depression of freezing point.

Elevation of Boiling Point and Ebullioscopic Constant

• Elevation of boiling point (ΔT_b) is the difference in boiling points of a solution and a pure solvent, given by ΔT_b = T_s - T_0.
• Ebullioscopic constant (K_b) is the elevation in boiling point observed when one mole of a non-volatile solute is dissolved in 1 kg of solvent.

Cryoscopic Constant

• Cryoscopic constant (K_f) is the depression in freezing point observed when one mole of a non-volatile solute is dissolved in 1 kg of solvent.

Electrolysis and Faraday's Laws

• Electrolysis is the chemical decomposition of an electrolyte by an electric current.
• Faraday's first law of electrolysis states that the amount of substance deposited or liberated at the electrode is proportional to the quantity of current passing through the electrolyte.
• Faraday's second law of electrolysis states that when the same quantity of current is passed through different electrolytes, the amount of substances deposited at the electrodes is inversely proportional to their equivalent weights.

Galvanic Cell and Voltaic Cell

• A galvanic cell or voltaic cell is an electrochemical cell that generates an electric potential difference through spontaneous redox reactions.

Kinetics and Rate Constant

• The half-life of a first-order reaction is given by t_(1/2) = 0.693 / k.
• The rate constant (k) can be calculated from the half-life of a first-order reaction.

Electrochemistry and Cell Reactions

• The mass of copper deposited at the cathode during electrolysis can be calculated using the formula m = (I x t) / (96500 x n).
• The standard Gibbs energy for a cell reaction can be calculated using the formula ΔG = -nFE.

Test your knowledge of Raoult's Law and Henry's Law in chemistry. Understand the concepts of Relative Lowering of Vapour Pressure and the relationship between partial pressure and mole fraction of a gas in a solution.