What instruments are used for evaporative concentration and cooling crystallization? Why? Why?

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• 1. What is the difference between and recrystallization? The difference between cooling crystallization and recrystallization?
• 2. Which three types of common metal crystal lattice forms are there?
• 3. After evaporation of m g of water from the solution having a mass fraction of a solute, it becomes V ml of a sodium hydroxide unsaturated solution having a mass fraction of 2 a of solute What is the concentration of the substance obtained?
• 4. When to cool the crystallization and cool the hot saturated solution? When will it be crystallized by evaporation?
• 5. The cause of formation of fiber structure, banded structure and deformation texture during cold working and their influence on metal properties are briefly introduced
• 6. Is the solution after crystal precipitation an unsaturated solution?
• 7. What is the crystallization process of unsaturated solution What is the process of crystal precipitation in unsaturated solution
• 8. Is it certain that crystals will precipitate from the unsaturated solution after a period of evaporation? Why?
• 9. To obtain salt crystals from a salt solution, the method can be A Decreasing temperature B Increase pressure C Evaporating solvent D Filtering
• 10. At 20°C, put 20g of sodium chloride into 100g of sodium chloride to prepare unsaturated solution. To saturate the solution, how many grams of sodium chloride need to be evaporated or how many sodium chloride crystals need to be added (The solubility of sodium chloride at 20.degree. C. is known to be 36 g At 20°C, put 20 g of sodium chloride into 100 g of sodium chloride to prepare an unsaturated solution. To saturate the solution, how many grams of sodium chloride need to be evaporated or how many sodium chloride crystals need to be added (The solubility of sodium chloride at 20.degree. C. is known to be 36 g
• 11. What is the number of electron number of manganese? What is the number of the outermost electrons in manganese?
• 12. What is the valence of the outermost 4 electrons Such as title
• 13. At 20°C, the solubility of salt is 36 g. At present,100 g and 200 g of saturated salt solution at 20°C are evaporated off 10 g of water at the same temperature. Algorithm Process and Text Analysis At 20°C, the solubility of salt is 36 salt is 36g. At present,100g and 200g of saturated salt solution at 20°C can evaporate 10g of water, and what are the precipitated crystals? To calculate the process and text analysis
• 14. At 20°C, the solubility of salt is 36 g. At this temperature, the mass fraction of solute in the saturated solution of salt
• 15. At t.degree. C.,200 g of a solution is evaporated,20 g of water is evaporated,8 g of crystal is precipitated, and 20 g of water is evaporated, and 12 g of crystal is precipitated. The solubility of a substance at t.degree. C. is () A.40 g B.50 g C.60 g D.100 g
• 16. 4.20°C, the solubility of NaC1 is 36g, what is the mass fraction of saturated sodium chloride solution at this temperature? 4. What is the mass fraction of is 36g at 20°C, what is the mass fraction of saturated sodium chloride solution at this temperature?
• 17. At 20°C, the solubility of sodium chloride is 36 g/100 g of water. If 500 g of saturated sodium chloride solution at 20°C is evaporated off 100 g of water, the temperature is still reduced to 20°C. Mass fraction of solute in the remaining solution after precipitation of several sodium chloride crystals
• 18. Q: If a certain amount of 14% potassium hydroxide solution is evaporated from 100 g of water, its mass is 28% and its volume is 125 ml, then what is the concentration of KOH after concentration? I have an answer.(I'd better be taught how to analyze and solve problems.) Thank you! Q: If a certain amount of 14% potassium hydroxide solution is evaporated from 100 g of water, its mass is 28% and its volume is 125 ml, then what is the concentration of concentrated KOH substance? I have the answer.(It's better to teach me how to analyze the problem.) Thank you!
• 19. A certain amount of 14% by mass of KoH solution, if it is evaporated off 100 g of water, its mass fraction is 28% by volume, and the amount of the substance after concentration is? A certain amount of 14% by mass of KoH solution, if it is evaporated off 100 g of water, will have a mass fraction of 28% and a volume of 80 ml of concentrated substance in the amount of?
• 20. After evaporation of mg water from the KOH solution with a mass fraction of W, the mass fraction became exactly 3 W and the volume was VL (no crystal precipitation in the solution) The mass concentration of the concentrated solution is? Use a comprehensive expression to express it, not to count. After evaporation of mg water from the KOH solution with a mass fraction of W, the mass fraction becomes exactly 3 W and the volume is VL (no crystal precipitation in the solution) The mass concentration of the concentrated solution is? Use a comprehensive expression to express it, not to count.