A6.0 gram sample of an unknown compound is dissolved in 125 g of water. the solutions freezing point is lowered to 1.38 c° below the freezing point of pure water. what is the molar mass of the sample? k for water is 1.86 c°/m.

Change in the freezing point = Kf * m

m = molality
Kf = 1.86 °C/m

m = Change in the freezing point / k = 1.38°C / 1.86 °C/m =0.742 m

m = #mol of solute / Kg of solvent

Kg of solvent = 125g/1000 g/kg = 0.125 kg.

#mol of solute = m* Kg of solvent = 0.742m * 0.125 kg =0.09275mol

Molar mass = 6. 0 g / 0.09275 mol = 64.7 g/mol

Answer charle's law

Van der waals forces are temporary electromagnetic forces established between uncharged atoms. some neutral molecules, when close together, can become temporarily “charged,” as electrons move around the atom. water is a polar molecule, the side of the molecule that the hydrogens bond to being more positive, and the opposite side bound to the lone pairs of electrons being more negative. this means that it participates in dipole-dipole interaction (non-polar exhibits dispersion forces), and it has the capacity for hydrogen bonding.