A 0.350g sample of a large biomolecule was dissolved in 15.0g of benzene, and the freezing point depression was determined to be 0.262oC. Calculate the molar mass of the biomolecule.

The molar mass of the biomolecule is 455.73 g/mol

Explanation:

∆T = m × Kf

m (molality) = ∆T/Kf

∆T = 0.262 °C, Kf of benzene = 5.12 °C/m

m = 0.262/5.12 = 0.0512 mol/kg

Molecular mass of the biomolecule = mass of biomolecule ÷ (molality × mass of benzene in kilograms) = 0.350 ÷ (0.0512 × 15/1000) = 0.350 ÷ 0.000768 = 455.73 g/mol

definition

                    entropy is a measure of the randomness or the extent of disorder of a chemical process.

                      enthalpy is a measure of the heat change of a reaction occurring at a constant pressure.

measurement units:

                        entropy is measured in joule per kelvin (jk⁻¹)   whereas enthalpy is measured in joule per mole (jmol⁻¹)

requirements:

                            entropy has no requirements or limits, and its change is measured by the division between the heat change of the chemical process and the temperature.

                              in contrast, enthalpy can only be related to the heat change of the reaction under standard conditions.