山东大学：《物理化学》课程教学资源（讲义资料）2020 Group work-5

(1) Please find the highest tree in the world from internet. Give its name and height This tree can bring water containing inorganic salts from the root to the very top through vessel. Please calculate the radius of the vessel tube based on capillarity. How many pumps should we used to elevate water to the same height? (2) Silica gel can be HCI into Na2SiO solution There is a lot of water (more than 90%) newly prepared silica gel Given that silica gel is hydrophilic solid and water forming concave surface inside its micropores If we make water to evaporate by heating, the structure of silica gel will collapse, and only silica gel with very small pore volume and poor adsorption can be obtained However, if we dry silica gel using supercritical drying, silica gel with high porosity can be get. Please give explanation to these (3)To transport glass plates, people usually put a piece of paper between two pieces of glass. Otherwise, water may condense in the space between two glass plates. Then it is difficult to separate the glass plates. Why is it easier for water vapor to condense between glass plate? Why is it difficult to separate glass with water layer between two

2020 Group work-5 (1) Please find the highest tree in the world from internet. Give its name and height. This tree can bring water containing inorganic salts from the root to the very top through vessel. Please calculate the radius of the vessel tube based on capillarity. How many pumps should we used to elevate water to the same height? (2) Silica gel can be fabricated by addition of HCl into Na2SiO3 solution. There is a lot of water (more than 90%) in the newly prepared silica gel. Given that silica gel is hydrophilic solid and water forming concave surface inside its micropores. If we make water to evaporate by heating, the structure of silica gel will collapse, and only silica gel with very small pore volume and poor adsorption can be obtained. However, if we dry silica gel using supercritical drying, silica gel with high porosity can be get. Please give explanation to these phenomena. (3) To transport glass plates, people usually put a piece of paper between two pieces of glass. Otherwise, water may condense in the space between two glass plates. Then it is difficult to separate the glass plates. Why is it easier for water vapor to condense between glass plate? Why is it difficult to separate glass with water layer between two plates?

(4)Water can rise spontaneously in hydrophili capillary to a certain height (h). Does this phenomenon contradict the second law of thermodynamics? Please make judgement and give your explanation (5) According to the classification of surfactants, please one typical surfactant for each type and give it structure, indicate its hydrophilic head and hydrophobic end polymerIc surfactant IonIc cationic Organometallic surfact oter oxa Reactant oil-soluble surfactant ether nonionicamine ixed nonionic-cationic nonlonic-anIonIc

(4) Water can rise spontaneously in hydrophilic capillary to a certain height (h). Does this phenomenon contradict the second law of thermodynamics? Please make judgement and give your explanation. (5) According to the classification of surfactants, please one typical surfactant for each type and give it structure, indicate its hydrophilic head and hydrophobic end