- 5 Liquid Nitrogen Which Boils At 196 C Is Used In Some Specialty Ice Cream Shops To Freeze Ice Cream Nearly Instant 1 (116.62 KiB) Viewed 40 times
as -21.1 degrees celsius. What is the molality of a salt water
solution with this freezing point? water has a Kf of 1.86
degrees celsius and a freezing point of 0.0 degrees celsius
5. Liquid nitrogen, which boils at -196 °C, is used in some specialty ice cream shops to freeze ice cream nearly instantly. Modem factories commonly use liquid ammonia as refrigerant to freeze ice cream at around -30°C. Before liquid ammonia was available, mixtures of water and table salt (NaCl) were used. Adding salt to water can lower its freezing point to as low as -21.1°C. What is the molality of a salt water solution with this freezing point? Water has a Kr of 1.86 °C/m and a freezing point of 0.0°C. A corollary colligative property to freezing point depression is boiling point elevation. In this case, a solution will begin to boil at a higher temperature than its corresponding pure solvent from the following equation: ATb = * K *m Here, AT. is the increase between the pure solvent and the solution boiling points, i is the van't Hoff factor for the solute, Kh is the molal boiling point elevation constant individual to the solvent, and m is the solution's concentration in units of molality. 6. Benzene has a Ko of 2.53 °C/m and a normal boiling point of 80.2 °C. Calculate the molality of a solution of benzene and an unknown nonelectrolyte compound that boils at a temperature of 95.6 °C. 7. If the solution in (4) was created by dissolving 15.62 g of unknown into 42.3 g benzene, calculate the molecular weight of the unknown compound in g/mol.