Alkali metal -Sodium( Na )-钠.ppt

1、,Lecturer:林海妍 10 chemical education class one Student number:2010364102,Alkali Metals-Sodium,Knowledge points:,Part one : review what we learnt last class,Part two : learn the new knowledge-the chemical properties of sodium,Part three: do some exercises,The physical properties of sodium,Sodium(Na),S

2、ilvery white,small,0.97g/cm3,97.81,882.9,good,good,Can be summarized as five words: white, soft, light, and guide,Chinese meaning: 白，软，轻，低，导,Chemical properties of sodium,Discussion:,1.Does sodium melt into a ball? Is there any other phenomenon ?Why?,2.What color changes happen in the solution as re

3、action takes place ? What is formed during the reaction between sodium and water?,I. Sodium reacts with water,Sodium and water reaction experiment phenomenon can be summarized as five words:,Floating, melting, tour, ring, red.,Float-sodium floats on water.,because the density of sodium is less than

4、water,Melt-sodium melts into a shiny ball.,Because of the low melting point of sodium, sodium reacts with water to release a lot of heat and make sodium melt,Tour-sodium ball walks in all directions,Because the reaction forms gases, and gases promote sodium swim rapidly in all directions,Pay attenti

5、on to observe phenomena carefully !,Red-solution is changed to red solution,Because generated the alkali sodium hydroxide(NaOH), solution contains phenolphthalein(酚酞）, phenolphthalein meet alkali and appear red.,Ring - the reaction process send out hiss , hiss sound.,Because reacting quickly , and f

6、orms gas. The generation of H2 in the air is burning and sends out the popping sound.,2Na + 2H2O = 2NaOH + H2,The chemical equation：,Do some exercises,1.Put water in a beaker ,drop phenolphthalein solution in it, then put a piece of sodium in this beaker ,and finish the following table.,Floating, Melting, tour, ring , red,2Na + 2H2O = 2NaOH + H2,2. Why cant we take sodium straight by hands?,Because sodium can reacts with water and forms the alkali sodium hydroxide. The sodium hydroxide i