# Blog

The Clausius Clapeyron Equation The Clausius-Clapeyron Equation is used to calculate the vapor pressure at another temperature if the vapor pressure is known at some temperature. ln(P2/P1) = ΔH/R(1/T1 – 1/T2) P1 & P2 – mmHg, T1 & T2 – K, R – 8.314J/mol.K , ΔH = J/mol Note that no pressure is given with […]

Raoult’s Law Of Non-Volatile Solute For Concentrated Solution Problem: The relative lowering of vapor pressure produced by dissolving 71.5g of a substance in 1000g of water is 0.00713. The molecular weight of the substance will be: P0 – Ps/P0 = n/(n + N) Or P0 – Ps/P0 = w/m/(w/m + W/M) n – moles of […]

Raoult’s Law Of Non Volatile Solutes For Dilute Solution Problem: Calculate the vapor pressure of the solution containing 35.5g of glucose (C6H12O6) per 100g of water at 25˚C. The vapour pressure of water at 25˚C is 23.75mmHg. (Molar mass of C6H12O6 = 180.16g/mol) Solution: Apply the formula: P0 – Ps/P0 = n/N Or P0 – […]

Raoult’s Law of Non Volatile Solute Raoult’s law states that the relative lowering of vapor pressure of a solution to pure solvent containing a non-volatile solute is equal to the mole fraction of the solute in the solution. The vapor pressure of a solution Ps is less than that of pure solvent P0. Thus, lowering […]

Raoult’s Law of Volatile Mixture Raoult’s law states partial pressure of a component in a solution is equal to its mole fraction multiplied by the vapor pressure of that component in pure state. P = P0.X P- V.P of component in the solution, P0– V.P of pure solvent, X-mole fraction of the component. The total […]

Calculating The Molecular Weight Of Solute From Osmotic Pressure π = iMRT π – osmotic pressure (atm), i-Van’t Hoff factor, M –concentration of solution (moles/L), R-0.0821 atm.L/mol.K, T – temperature (K) Problem: The degradation of cellulose produces cellobios, a sugar substance. If 250.0 mL of aqueous solution containing 12.00g of cellobios at 25.0˚C gives rise […]

Calculating The Osmotic Pressure Of A Solution Osmotic pressure is the measure of the tendency of a solution to take in water by osmosis. It is directly proportional to its concentration (molarity) at constant temperature. π = iMRT π – osmotic pressure (atm), i-Van’t Hoff factor, M –concentration of solution (moles/L), R-0.0821 atm.L/mol.K, T – […]

Calculating The Molar Mass of The Unknown Compound From Boiling Point Elevation Problem: 4.20g of an unknown compound is dissolved in 120.0g of benzene. The boiling temperature of the solution is 86.60˚C. The boiling temperature of pure solvent, benzene, is 80.10˚C; Kb = 2.53˚C/m. Calculate the molar mass of the unknown compound. Solution: Change […]

Calculating The Boiling Point of Solution From Boiling Point Elevation Problem: Calculate the boiling point of a 15% solution of cane sugar (C12H22O11). Molal elevation constant for water is 0.52K kgmol-1. The boiling point of water is 373K and the molar mass of cane sugar = 342.30g/mol. Solution: If the mass of the solution is […]

Calculating The Boiling Point Elevation Boiling point elevation is the process in which adding a non-volatile solute to a solvent increases the boiling point of the solvent. ΔTb = i .Kb. m or ΔTb = i .Kb.(w/M). (1000/W) ΔTb – Boiling point elevation, i- Vant’ hoff factor, Kb – molal F.P. depression constant, w- mass […]