![]() ![]() Neon and Argon both are non-polar gases and London dispersion forces which depend upon the size of molecules, are the only forces present in their molecules. Due to small size, neon molecules have weaker London dispersion forces while Argon has stronger London dispersion forces due to large size of its molecules. Hence neon has less boiling point a as compare to Argon. Q.2 vi) Different liquids have different rates of evaporation even at the same temperature.ĭifferent liquids have different rates of evaporation even at the same temperature because the strength of intermolecular forces is different in different liquids. Stronger the intermolecular forces, slower will be the rate of evaporation and vice versa.įor example, rate of evaporation of water is slower than that of ether, because water has strong hydrogen bonding and ether has weak London forces.ĪDVERTISEMENT Q.2 vii) Earthenware vessels keep water cool even in hot summer days. Vacuum distillation can be used to avoid decomposition of a sensitive liquid.Įarthenware vessels have porous surface. Water molecules come on the surface through these pores and evaporate. These molecules take energy away from the filled water and water remains cool even in hot summer days. The distillation carried out under reduced pressure is called vacuum distillation. High boiling sensitive liquids cannot be purified at normal temperature because they decompose before their boiling points are reached. For example, glycerine boils at 290 oC at normal atmospheric pressure, but it decomposes at this temperature. vacuum, the boiling point of glycerine decreases to 210 oC at 50 mmHg. So it can be distilled easily under vacuum. Q.2 viii) A liquid boils at different temperatures at sea-level and at mountains.īoiling point of a substance is the temperature at which vapour pressure of the liquid becomes equal to the external pressure. So the boiling point varies with external pressure. Note the large number of particles in the gas.At sea-level, external pressure is high and more heat is required to equalize vapour pressure to the external pressure that is why boiling point is high. Microscopic equilibrium between gas and liquid at high temperature. Note the small number of particles in the gas. Microscopic equilibrium between gas and liquid at low temperature. At a lower temperature, fewer molecules have sufficientĮnergy to escape from the liquid or solid.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |