高中化学必修1 第四章知识点.docx

1、高中化学必修1 第四章知识点高中化学必修1 第四章知识点（High school chemistry 1 chapter 4 knowledge points）The fourth chapterThe first section of siliconIn nature, silicon is in the form of silica and silicates, and there is no such thing as siliconThe properties of silicon dioxide: high melting point, large hardness and inso

2、luble in water1. Silica is acidic oxide: can react with alkali or alkaline oxideSiO2 naoh + 2 = Na2SiO3 + H2OThe formation of sodium silicate is more viscous, so the glass reagent of the acid solution is not used for the glass, and the rubber plug is usedSiO2 + CaO = CaSiO3Hydrofluoric acid is the o

3、nly acid that reacts with silicon dioxideSiO2 + 4HF = SiF4 arrow + H2OHydrofluoric acid can corrode the glass and can be used to sculpt the glass, which cant be used in glass reagent bottles, but plastic bottles.Application of silica: fiber optics, silicon, glass, handicraft (quartz, crystal, agate)

4、The preparation of silicic acid: Na2SiO3 + 2HCl = 2NaCl + H2SiO3Silicic acid is a white colloidal solid that is insoluble in water and is more acidic than carbonatedTo the sodium silicate solution, the carbon dioxide is formed in white silicateNa2 sio3 + CO2 + H2O = Na2CO3 + H2SiO3Silica gel can be

5、desiccant after dehydrationThe aqueous solution of sodium silicate is called water glass, which can be used as soap filler, wood fire retardant and adhesive.Note: the water glass (i.e., sodium silicate solution) is sensitive to the CO2 reaction in the air and produces H2SiO3. It should be sealed and

6、 preservedApplication of silicate: ceramic, glass and cementSimple silicon: properties: metallic black solid with metallic luster, high melting point, high hardness, stable at normal temperatureMethod:Normal temperature can react with alkali solution and HFSi + naoh + 2 H2O + 2 = = Na2SiO3 h2 writeS

7、i plus 4HF = SiF4 + 2H2USES:Semiconductor materials, photovoltaic (computer chips, semiconductor transistors,)Section ii the element of enrichment in seawater - chlorine1. The presence of chlorine: in nature chlorine exists mainly in sea water, mainly in Cl - form.2. Physical properties of chlorine

8、gas: a gas with a pungent smell and poisonous yellow and green,It is soluble in water (1:2), low temperature and easy to liquefy when pressurized.3. Chemical properties of chlorine gas:A, chlorine gas and metal reactions2 Na + Cl2 = = 2 NaCl (yellow flame, white smoke)Cu + Cl2 = = CuCl2 (palm yellow

9、 smoke, a small amount of water with a green solution, such as a large amount of water in blue)2 Fe + 3 Cl2 = = 2 FeCl3 (not generating FeCl2) (brown smoke)B, chlorine gas and nonmetallic reactionsH2 + Cl2 = = = 2HCl (white fog) (explosion under light of Cl2 and H2)2 P + 3Cl2 (a small amount) = = 2

10、PCl3 (white fog) (white smoke when chlorine and P are lit)2 P + 5Cl2 (lots) = = 2 PCl5 (white smoke)(combustion: the intense chemical reaction of any glowing heat is called combustion. Combustion does not have to be oxygen to participate. The nature of combustion is the REDOX reaction.)C, chlorine a

11、nd waterCl2 + H2O HCl + HClO (Cl2 do both oxidant and reducing agent)Hypochlorous acid (HClO) unary weak acid (acid is weaker than carbonic acid), strong oxidation (sterilization, disinfection), bleaching, unstable and easy to decompose.2HClO = = 2HCl + O2New chlorine water composition (particle) :

12、Cl2, H2O, HClO, H +, Cl -, ClO -Chlorine water composition (particle) : H2O, H +, Cl -Dry chlorine gas is not bleached, and the essence of bleaching is HClO in chlorine water.D, the reaction with a base solutionCl2 + 2OH minus = = Cl - + ClO - + H2O (using sodium hydroxide to absorb excess Cl2)The i

13、ngredients of bleach, CaCl2 and Ca (ClO) 2The active ingredient of bleaching powder, Ca (ClO) 2Bleaching principle of bleaching powder: the process of producing hypochlorous acid by contact with CO2 in the air.E. Reaction of chlorine gas to other compounds (strong oxidant) :Reductive substances such

14、 as Fe2 +, Br -, I -, SO2, SO32 -. The substance can be oxidized by chlorine gas.2 fecl2 + Cl2 fecl3 = = 22 nabr + nacl + Br2 Cl2 = = 22 nai + Cl2 nacl + I2 = = 2H2S + Cl2 = = S + 2 HCLNa2SO3 + H2O + nacl + - H2SO4 Cl2 = = 2F. Laboratory preparation of chlorine gasSection 3 oxides of sulfur and nitr

15、ogenSulfur: yellow powder, insoluble in water, soluble in alcohol, soluble in CS2.S and metal react with metal sulfide (such as Cu2S, FeS, etc.)SO2: colorless, pungent and pungent, noxious gas, with a denser than air, easy to liquefy, easy to dissolve in water, 1 volume of water dissolved in 40 volu

16、mes of SO2. Its the acid anhydride of H2SO3.SO2 + H2O H2SO3 SO2 + Ca (OH) 2 = CaSO3 + H2OThe bleaching of SO2 makes the magenta color fade, the non-oxidized reduction reaction, temporary, can only make the purple litmus test liquid red, cannot make it fade. SO2 can be used to kill bacteria.The weak oxidation of SO2: SO2 + 2H2S = 3S + 2H2OStrong reducib