Question

U The compound solute) wils nol dissolved cop y When Soluto was not completely dissolved mass Of SOUTC novic be tricen i ess but we are using mass of solute as higirur Vore so the calculated moacviar mass would be more than the true valve Of Molecular MASS. c) A foreign solute was already present in the solvent When a farcign Joure is preprost Arcady presento mass of Solute Should be thon more than Wb, with the uſe of w the calculated molecular mass would be less than true Value MOUCurar mass Bothtyeezing point of Saint IS CALCIO Along w foreign SOLUTC, then calcolored Moiar mass would be d) The thermometer is not calibrated correctly and as a result it displays temperatures that are always 1.2 °C higher than the actual temperature. &Tf would be less if tomp reading is always greater 1.2° the calculated moucular MASS would the greater than the true valu of molar MASS. But if frezina p of solvent is NISO calciated by same thermometer than the Coiculatea moucular mass would be same as the true value of molar mass. 2. Why does the pure solvent give a flat line while it is crystallizing, whereas the solution gives a line that slopes downward?

Answer 1

Solution:

The crystallization curve of pure solvent give a flat line because the temperature remains constant while the liquid is crystallizing. Thus, the flat portion of curve represents freezing temperature of solvent.

The crystallization curve for solution is slightly sloped downward. This is due to freezing of solvent. As the pure solvent freezes, the molality of the solute in solution becomes more concentrated, thus the freezing point continues to drop.