高中化学复习(Senior high school chemistry review)

高中化学复习（Senior high school chemistry review）
A common name:
Inorganic part:
Soda, soda, natural alkali, alkaline soda: Na2CO3: NaHCO3: Na2S2O3 (soda gypsum gypsum plaster): CaSO4.2H2O: 2CaSO4: CaF2?.H2O fluorite barite: BaSO4 (non-toxic) ammonium carbonate limestone, marble: CaCO3: NH4HCO3: CaO: NaCl salt lime slaked lime, slaked lime (: Ca OH) 2: Na2SO4 7H2O (mirabilite? Laxative) caustic soda, caustic soda, caustic soda: NaOH melanterite: FaSO4? 7H2O dry ice: CO2 alum: KAl (SO4) 2? 12H2O bleaching powder: Ca (ClO) 2, CaCl2 (mixture) salts: MgSO4? CuSO4 7H2O, brochantite Chalcanthite? 5H2O: hydrogen peroxide goslarite H2O2: ZnSO4? 7H2O: SiO2 silica, quartz corundum: Al2O3 water glass, sodium silicate, iron oxide, iron ore mineral rubber: Na2SiO3: Fe2O3: Fe3O4 magnetite pyrite, pyrite: FeS2 Verdigris, malachite: Cu2 (OH) 2CO3 siderite: FeCO3: Cu2O: Ca Bordeaux cuprite (OH 2) and CuSO4 Ca (OH): LSSS and 2 main components: Na2SiO3, S glass CaSiO3, SiO2 superphosphate (the main component): Ca (H2PO4) 2 and CaSO4 (the main component of triple superphosphate Ca (H2PO4) 2): natural gas, biogas, pit gas (the main component): CH4 water gas: CO and H2 ammonium ferrous sulfate (blue green): Fe (NH4) 2 (SO4) 2 dissolved in water was pale green
Photochemical smog: a toxic gas Aqua NO2 produced in the light of the thick HNO3 thick HCl according to the volume ratio of 1:3 blend.
Thermites: Al + Fe2O3 or other oxides. Urea: CO (NH2) 2
Organic part:
Chloroform: CHCl3 calcium carbide: CaC2, calcium carbide gas: C2H2 (acetylene) TNT: three nitro toluene
That is a good HCFC refrigerant, toxic, but the destruction of the O3 layer. Alcohol and ethanol: C2H5OH
Pyrolysis gas components (petroleum cracking): alkenes, alkanes, alkynes, H2S, CO2, CO etc..
Composition of coke oven gas (coal carbonization): H2, CH4, ethylene, CO and so on. Acetic acid: glacial acetic acid and vinegar CH3COOH
Glycerol, glycerol: C3H8O3: phenol formaldehyde phenol: formaldehyde HCHO
Faure Marin: 35% - 40% formic acid aqueous solution of formaldehyde, formic acid HCOOH
Glucose: C6H12O6 fructose: C6H12O6 sucrose: C12H22O11 maltose: C12H22O11 starch: (C6H10O5) n
Stearic acid: C17H35COOH: C17H33COOH: C15H31COOH oleic acid palmitic acid
HOOC - COOH (oxalic acid: oxalic acid can make the blue ink fade, strongly acidic, thermal decomposition into CO2 and water, the KMnO4 acidic solution.).
Two, color
Iron: iron powder is black; a block of solid iron is silvery white.
Fe2+ - light green Fe3O4 - Black crystal Fe (OH) 2 - white precipitate
Fe3+ - yellow Fe (OH) 3 - reddish brown precipitate Fe (SCN) 3 - red blood solution
Fe FeO: black powder (NH4) 2 (SO4) 2 - Blue Green
Fe2O3 - red brown powder
Copper: simple substance is purple red
Cu2+ - blue CuO - Black Cu2O - red
CuSO4 (anhydrous) - white CuSO4? 5H2O - Blue
Cu2 (OH) 2CO3 - Green
Cu (OH) 2 - blue [Cu (NH3) 4]SO4 - dark blue solution
FeS - black solid
BaSO4, BaCO3, Ag2CO3, CaCO3, AgCl, Mg (OH) 2, is a white precipitate tribromophenol
Al (OH) 3 white flocculent H4SiO4 (silicic acid) white colloidal precipitate
Cl2, yellow green F2, chlorine gas, light yellow green Br2 red brown liquid
I2, HF, HCl, purple black solid HBr, HI is a colorless gas in the air were formed in the fog
CCl4 - colorless liquid with a density greater than water and immiscible with water
Na2O2 - pale yellow solid Ag3PO4 - yellow precipitate S - yellow solid AgBr - pale yellow precipitate
AgI - O3 - light blue yellow precipitate gas SO2 colorless gas, irritating odor, poisonous
SO3 - colorless solid (boiling point 44.8 degrees) magenta solution - red hydrofluoric acid: HF - etching glass
N2O4, NO - colorless gas NO2 - reddish brown gas
NH3: colorless, irritating odor gas KMnO4-- - MnO4- - purple purple
Three, phenomenon:
1, the reaction between aluminum and hydrochloric acid is exothermic, and the reaction of Ba (OH) 2 with NH4Cl is endothermic;
2, Na and H2O (with phenolphthalein) reaction, melting, floating on the surface, rotation, the gas is released; (melting, floating, swimming, hiss, red)
3, flame reaction: Na yellow, K purple (through the blue cobalt glass) Cu green, Ca, brick red, Na+ (yellow), K+ (purple).
4, Cu filaments burn in Cl2 to produce brown smoke; 5 and H2 burn in Cl2, a pale flame;
6, Na combustion in Cl2, produce a lot of white smoke; 7, P burning in Cl2, produce a lot of white smoke;
8, SO2 into the magenta solution first fade, and then restore the original color after heating;
9, NH3 and HCl meet, produce a lot of white smoke; 10, aluminum foil in oxygen burning, produce dazzling white light;
11, the magnesium bar burns in the air, produces dazzling white light, burns in the CO2, produces the white powder (MgO), produces the black smoke;
12, iron wire burning in Cl2, produce brown smoke; 13, HF corrosion glass: 4HF + SiO2 = SiF4 + 2H2O
14, Fe (OH) 2 is oxidized in air: change from white to grey and green to red brown;
15. At room temperature: Fe and Al are passivated in
concentrated H2SO4 and concentrated HNO3;
16, Xiang Sheng has phenol solution in the test tube drops into the FeCl3 solution, the solution assumes the purple, the phenol meets the air to be pink.
17, the protein in case of concentrated HNO3 yellow, burned when there are burnt feathers smell;
18. Burn in the air: S - weak light blue flame - H2 - light blue flame H2S - light blue flame
CO - blue flame CH4 - bright and blue flame, S burns in O2 - bright blue purple flame.
19. characteristic response phenomenon:
20. light yellow solid: S or Na2O2 or AgBr
21., magenta solution fading gas: SO2 (after heating and restore red), Cl2 (after heating does not restore red)
22., colored solution: Fe2+ (light green), Fe3+ (yellow), Cu2+ (blue), MnO4- (purple)
Colored solids: red (Cu, Cu2O, Fe2O3), reddish brown, [Fe (OH), 3]
Blue [Cu (OH) 2] black (CuO, FeO, FeS, CuS, Ag2S, PbS)
Yellow (AgI, Ag3PO4), white [Fe (0H) 2, CaCO3, BaSO4, AgCl,
BaSO3]
Colored gas: Cl2 (Huang Lvshai) and NO2 (red brown)
Four, regular rules used in exams:
1, solubility law - see solubility table; 2, commonly used acid and alkali indicator color range:
The color range of indicator PH
Methyl orange 3.1 red 3.1 - 4.4 orange >4.4 yellow
< 8 8 - 10 colorless phenolphthalein red light red >10.0
< 5.1 5.1 - 8 litmus red purple blue >8.0
3, on inert electrode, the order of discharge of various ions:
Cathode (electronic capacity):
Au3+, >Ag+>Hg2+, >Cu2+, >Pb2+, >Fa2+, >Zn2+, >H+,, >Al3+>Mg 2+, >Na+, >Ca2+, >K+
Anode (electron loss ability): S2-, >I-, >Br - >Cl-, >OH- > oxygen radical
Caution: if the metal is used as an anode, the anode itself will undergo oxidation-reduction reactions (Pt, Au, except for electrolysis)
4. Double hydrolysis ion equation writing: (1) write the
hydrolysis ion on the left and write the hydrolysate on the right;
(2) trim: trim the charge on the left and trim the other atoms on the right. (3) H and O are rough and add water over there.
Example: when Na2CO3 is mixed with a AlCl3 solution:
3 CO32- + 2Al3+ + 3H2O = 2Al (OH): 3CO2 = 3 +
5. Write the equation for the total electrolysis reaction: (1) analysis: what is the reactant and the product; (2) Pei Ping.
Example: KCl: 2KCl + 2H2O electrolytic solution = H2 = Cl2 = 2KOH + +
Trim: 2KCl + 2H2O = H2 = Cl2 = 2KOH + +
6, a chemical reaction method in two electrode reaction: (1) to write 2.5 electrons reaction; (2) consider the reaction of the environment (acidic or alkaline); (3) the number and the atomic charge is equal to the number of two sides.
Example: the reaction in the battery is: Pb + PbO2 + 2H2SO4 = 2PbSO4 + 2H2O, write the electrode reaction as the primary battery (discharge).
Write 2.5 responses: Pb - 2e- = PbSO4, PbO2, +2e-, PbSO4
Analysis: in acidic environment, fill up other atoms:
Should be: negative: Pb + SO42--2e- = PbSO4
Positive: PbO2 + 4H+ + SO42- +2e- = PbSO4 + 2H2O
Note: when charging, it is electrolysis, and the electrode reaction is the reverse of the above electrode reaction:
For: cathode: PbSO4, +2e- = Pb + SO42-
Anode: PbSO4 + 2H2O, -2e- = PbO2 + 4H+ + SO42-
7, in the identical solution calculation problems common to the atomic identity, identity, identity, ion charge, power electronic identity identity, the methods used are: mass conservation, difference method, normalization method, limit method and method. (non oxidation reduction reactions: atomic conservation, charge balance, mass balance, redox reactions: much more electronic conservation)
8, the same ion structure of the electron layer, the more the number of nuclear charge, the smaller the radius of ions;
9. Melting point of crystal: atomic crystal > ionic crystal > molecular crystal; the atomic crystal learned in secondary school is Si, SiC, SiO2= and diamond. The melting point of an atomic crystal is based on the atomic radius:
Diamond > SiC > Si (because of atomic radius: Si>, C>, O)
10, molecular crystal melting and boiling point: composition and structure of similar substances, the greater the molecular
weight, melting, boiling point higher.
11, colloid charged: Generally speaking, metal hydroxide, metal oxide colloidal particles with positive, non-metallic oxides, metal sulfide colloidal particles with negative electricity.
12. Oxidation: MnO4-, >Cl2, >Br2, >Fe3+, >I2, >S=4 (+4, S)
Example: I2, +SO2 + H2O = H2SO4 + 2HI
13, the solution containing Fe3+ is generally acidic. 14. Hydrogen bonding substances: H2O, NH3, HF, CH3CH2OH.
15, ammonia (ethanol solution) density is less than 1, the greater the concentration, the smaller the density, sulfuric acid density is greater than 1, the greater the concentration, the greater the density, the density of 98% concentrated sulfuric acid is: 1.84g/cm3.
16, whether the ion coexistence: (1) whether there is precipitation, gas release; (2) whether there is a weak electrolyte generation; (3) whether the redox reaction occurred; (4) whether the formation of complex ion [Fe (SCN) 2, Fe (SCN) 3, Ag (NH3) + [Cu (NH3) 4]2+]; (5) whether the double hydrolysis.
17, the earth's crust: the most content of metal elements is - Al content of the most non-metallic elements is - O, HClO4 (perchloric acid) - is the strongest acid
18, the lowest melting point metal is Hg (-38.9C. ) the highest melting point is W (w 3410c); the least dense (common) is K; the highest density (common) is Pt.
19, when the pH value of the rain is less than 5.6, it becomes acid rain.
20, organic acid or oxalic acid: acid > > > > > benzoic acid ethyl carbonate phenol >HCO3-
21, pay attention to organic identification, use water and water of the two substances.
Identification: ethyl acetate (insoluble in water),
Floating) and bromobenzene (insoluble in water, precipitation) and acetaldehyde (water soluble), water can be.
22. Substitution reactions include halogenation, nitration, sulfonation, hydrolysis of halogenated hydrocarbons, hydrolysis of esters, esterification, and so on;
23, the simplest of the same organic matter, no matter what proportion of mixing, as long as the total mass of the mixture must be, the total combustion of CO2, H2O and the amount of O2 is unchanged. Identical to the CO2, H2O, and O2 consumed by a single component in that mass.
24, the bromine faded substance as follows, but faded different reasons:
Alkenes and alkynes (addition of unsaturated hydrocarbons, phenol (fade), replace fade) ethanol, aldehyde, formic acid, oxalic acid, glucose (oxidation fade), organic solvent [CCl4, chloroform, bromobenzene, CS2 (density greater than water), hydrocarbons, benzene, benzene, esters (low density Yu Shui) the extraction and fade].
25, silver mirror reaction can occur are: formaldehyde, formic acid, formate, formyl ammonium (HCNH2O), glucose, fructose, maltose, can occur in the silver mirror reaction. (also responsive to Cu (OH) 2)
The formula for computing is generally: - CHO - 2Ag
Note: when the amount of silver ammonia solution, formaldehyde oxidation special: HCHO + H2CO3: 4Ag
The reaction type: HCHO +4[Ag (NH3) 2]OH (NH4) = 2CO3 + 4Ag + 6NH3 = 2H2O + down arrow
26. The method of colloid precipitation: (1) adding electrolyte;
(2) adding the opposite colloid; (3) heating.
Common colloid: liquid sol: Fe (OH) 3, AgI, milk, soybean milk, porridge, etc.; aerosols: fog, clouds, smoke, etc.; solid sol: colored glass, smoke crystal, etc..
27, pollution of atmospheric gases: SO2, CO, NO2, NO, in which SO2 and NO2 formed acid rain.
28, environmental pollution: air pollution, water pollution,
soil pollution, food pollution, solid waste pollution, noise pollution. Industrial three wastes: waste residue, waste water, waste gas.
29, at room temperature (20C) The solubility is more than 10 grams - soluble; more than 1 grams soluble; less than 1 grams; slightly soluble; less than 0.01 grams - insoluble.
30, the body water content of about 2/3 of the body mass. The total amount of fresh water on the ground is less than 1% of the total amount of water. The three major fossil fuels in the world today are coal, oil, and natural gas. Petroleum contains mainly elements of C and H.
31, pig iron containing C in: 2% - 4.3% steel containing C quantity in: 0.03% - 2%. Salt: NaCl contains MgCl2 and CaCl2, because the MgCl2 water, so salt deliquescent. HNO3 also formed thick fog in the air. The solid NaOH absorbs water easily in the air and forms a solution.
32, gas solubility: at a certain pressure and temperature, the 1 volume of water reached saturation state when the volume of gas.
Five. Characteristic reactions in inorganic reactions
1. react with alkali to produce gas
(1)
(2) ammonium salt:
2. react with acids to produce gas
(1)
(2)
3.Na2S2O3 reaction with acid precipitation and both produce gas: S2O32-+2H+=S: +SO2 = +H2O
4. react with water to produce gas
(1) simple substance
(2) compound
5. strong double hydrolysis
6. can not only react with acid, but also react with alkali
(1) Al (2): Elemental compounds: Al2O3, Al (OH) 3, weak acid weak base salt, acid salt, amino acid.
7. react with Na2O2
8.2FeCl3+H2S=2FeCl2+S: +2HCl
9. electrolysis
10. thermit reaction: Al+ metal oxide metal +Al2O3
11.Al3+ Al (OH) 3 AlO2-
12. responses: 2H2S+SO2=3S+2H2O
4NH3+6NO 4N2+6H2O
13. exchange reaction:
(1) metal to metal
(2) metal to nonmetal
(3) nonmetal to nonmetal
(4) nonmetal to metal
14, some special reaction types:
The compound + + compounds such as elemental compounds:
Cl2 + H2O + O2、、、H2S NH3 + O2、CH4 + O2、Cl2 +考察
⑵化合物+化合物化合物+单质
没有、NH3 + H2S + SO2、Na2O2＋H2O、NaH + H2O + CO2、过氧化钠、CO + H2O
⑶化合物+单质化合物
PCl3 + Cl2、Na2SO3 + O2、FeCl3 +铁、FeCl2 + Cl2、CO + O2、Na2O + O2
14。

三角转化：
15。

受热分解产生2种或3种气体的反应：
（1）铵盐
（2）硝酸盐
16。

特征网络：
（1）
①
②
③
④
（2）a—
一个为弱酸的铵盐：（NH4）2CO3或碳酸氢铵（NH4）；2s或NH4HS；（NH4）2SO3或NH4HSO3
（3）无机框图中常用到催化剂的反应：
17。

关于反应形式的联想：
1。

热分解反应：典型的特征是一种物质加热（1变2或1变3）。

含有电解熔融的Al2O3来制备金属铝、电解熔融的NaCl来制备金属钠。

2。

两种物质的加热反应：
六、常见的重要氧化剂、还原剂
氧化剂还原剂
活泼非金属单质：X2、O2、的活泼金属单质：Na、毫克、铝、锌、铁
某些非金属单质：C、H2的、
高价金属离子：Fe3+、
不活泼金属离子：Cu2+、其它：〔Ag（NH3）2〕+、新制Cu（OH）低价金属离子：Fe2+、
非金属的阴离子及其化合物：
S2、H2S、我、嗨、NH3、Cl-、HCl、Br-、HBr
含氧化合物：
NO2、N2O5、MnO2、过氧化钠、、HClO、
、浓硫酸硝酸、Ca（ClO）、NaClO 2、KClO3、
高锰酸钾、王水低价含氧化合物：
公司、SO2、H2SO3、Na2SO3、Na2S2O3、NaNO2、
草酸、含町的有机物：醛、甲酸、甲酸盐、甲酸某酯、葡萄糖、麦芽糖等
既可作氧化剂又可作还原剂的有：
、的、SO32- HSO3-、H2SO3、SO2、NO2-、Fe2+等，及含町的有机物
七、反应条件对氧化－还原反应的影响。

1。

浓度：可能导致反应能否进行或产物不同
8hno3（稀）＋3cu = = 2no↑＋2cu（NO3）2＋4H2O
4hno3（浓）＋铜= = 2NO2↑＋Cu（NO3）2＋2H2O
S + 6hno3（浓）= = = H2SO4 + 6no2↑+ 2H2O
3S + 4 HNO3（稀）= = = 3so2 + 4no↑+ 2H2O
2。

温度：可能导致反应能否进行或产物不同
氯气+ 2naoh ===== NaCl + NaClO + H2O
6naoh 3Cl2 + ===== 5nacl +氯酸钠+ 3H2O
3。

溶液酸碱性。

2S2 -＋SO32-＋6h +＝3s↓＋3H2O
5cl -＋ClO3-＋6h +＝3Cl2↑＋3H2O
S2、SO32-、Cl-、ClO3-在酸性条件下均反应而在碱性条件下共存。

Fe2+与NO3-共存，但当酸化后即可反应。

3fe2 +＋NO3-＋4H +＝3fe3 +＋没有↑＋2H2O
一般含氧酸盐作氧化剂时，在酸性条件下，氧化性比在中性及碱性环境中强故酸性KMnO4溶液氧化性较强。

4。

条件不同，生成物则不同
1、2p＋3Cl2点燃= = = 2pcl3（Cl2不足）；2p＋点燃= = = 2 5cl2 PCl5（Cl2充足）
2、2h2s＋3O2点燃= = = 2H2O＋2SO2（O2充足）；2h2s＋O2点燃= = = 2H2O＋2s（O2不充足）
3、4na＋O2缓慢氧化===== 2na2o 2na＋O2点燃= = =过氧化钠
4、Ca（OH）2＋适量= = = = co2co2 CaCO3↓＋H2O；Ca（OH）2＋2CO2（过量）= = Ca（HCO3）2
5、C＋点燃= = = CO2 O2（O2充足）；2 C＋点燃= = = 2co O2（O2不充足）
6, 8HNO3 (rare) 3Cu==2NO hav'e 2Cu (NO3) 24H2O 4HNO3 (strong) Cu==2NO2 hav'e Cu (NO3) 22H2O
7, AlCl33NaOH==Al (OH): 3 3NaCl; AlCl34NaOH (excess)
==NaAlO22H2O
8, NaAlO24HCl (excess) ==NaCl2H2OAlCl3 NaAlO2HClH2O==NaClAl (OH): 3
9, Fe6HNO3 (hot and concentrated) ==Fe (NO3) 33NO2 hav'e 3H2O FeHNO3 (cold, thick), (passivation)
10, Fe6HNO3 (hot and concentrated) Fe ====Fe (NO3) 33NO2 hav'e 3H2O
Fe4HNO3 (hot and concentrated) Fe ====Fe (NO3) = 22NO2 excess 2H2O
11, Fe4HNO3 (dilute) Fe ====Fe (NO3) 3NO hav'e 2H2O 3Fe8HNO3 (dilute) Fe excess ====3Fe (NO3) 32NO hav'e 4H2O
12, C2H5OH CH2=CH2 = H2O C2H5OHHOC2H5 C2H5OC2H5H2O
13, Cl2 Fe, HCl
3Cl2 light - (HCH)
14, C2H5Cl + NaOHH2O, C2H5OH + NaCl C2H5Cl + NaOH, CH2 = CH2 = alcohol + NaCl + H2O
15, 6FeBr23Cl2 (lack of) ==4FeBr32FeCl3 2FeBr23Cl2 (excess) ==2Br22FeCl3
Eight. Ion coexistence
Whether ions can coexist in a large number of solutions involves the comprehensive knowledge of the properties of ions and the acidity and basicity of solutions. Any solution that causes a significant change in the concentration of ions in the solution can not coexist in large quantities. Such as the formation of insoluble, difficult to ionize, gaseous substances, or can be converted into other kinds of ions (including oxidation reduction reaction)
Generally consider the following aspects
1. weak base cations exist only in acidic solutions such as Fe3+, Al3+, Zn2+, Cu2+, NH4+, Ag+ and so on, which can not coexist with OH- in large quantities
2. weak acid anions are found only in alkaline solutions. Such as CH3COO-, F-, CO32-, SO32-, S2-, PO43-, AlO2-, and H+ can not coexist in large numbers
3. in the weak acid anion strong acid or strong alkaline solution were not large. They coexist in acid (H+) will produce weak acid molecules; in case of alkali (OH-) generate salt and water. Such as: HSO3-, HCO3-, HS-, H2PO4-, HPO42- etc.
4., if the anion and cation can be combined with each other to produce insoluble or slightly soluble salts, they can not coexist in large numbers
Such as: Ba2+, Ca2+ and CO32-, SO32-, PO43-, SO42-, etc., Ag+ and Cl-, Br-, I-, etc., Ca2+ and F-, C2O42- and so on
5. if the double hydrolysis reaction of anion and cation can not coexist in a large amount
Such as: Al3+ and HCO3-, CO32-, HS-, S2-, AlO2-, ClO-, SiO32- and so on
Fe3+ and HCO3-, CO32-, AlO2-, ClO-, SiO32-, C6H5O-, etc., NH4+ and AlO2-, SiO32-, ClO-, CO32- and so on
6., if the anion and cation can be oxidized, a reduction reaction can not coexist in large numbers
Such as: Fe3+ and I-, S2-; MnO4- (H+) and I-, Br-, Cl-, S2-, SO32-, Fe2+, etc.; NO3- (H+) and the above anions;
S2-, SO32-, H+
7. cannot coexist in large amounts because of complexation or other reactions
Such as: Fe3+ and F-, CN-, SCN-, etc.; H2PO4- and PO43- will generate HPO42-, so the two do not coexist
Nine, the common error and cause analysis of ion equation
1. basic rules of ion equation writing: (write, dismantle, delete, check, write in four steps)
(1) and fact: ion reaction should accord with the objective fact, not conjecture and reaction products.
(2) correct: the use of chemical and ionic symbols is correct and reasonable.
(3) the actual number: "=" "" "," "up" and "down" in line with the actual symbol.
(4) two conservation: the number of atoms and the number of charges on both sides must be conserved (in oxidation-reduction reactions, the total number of electrons obtained by the oxidant in the ionic equation is equal to the total number of electrons lost by the reducing agent).
(5) Ming type: distinguish between types, pay attention to a small amount, excessive, etc..
(6) check the fine: in conjunction with writing ion equation prone to errors, careful inspection.
For example: (1) contrary to the objective facts of the reaction
Such as: Fe2O3 and hydrogen iodate: Fe2O3 + 6H+ = 2, Fe3+ + 3H2O: cause to ignore the oxidation reaction between Fe3+ and I-
(2) violating the conservation of mass or the law of conservation of charge and the balance of electronic gain and loss
Such as: FeCl2 solution through Cl2:Fe2+ + Cl2 = Fe3+ + 2Cl- error due to: electronic gains and losses are not equal, the ion charge is not conserved
(3) confusion of chemical formula (molecular formula) and ionic writing form
Such as: NaOH solution into HI:OH- + HI = H2O + I- error due to: HI mistaken for weak acid
(4) reaction conditions or environment are not divided:
Such as: sodium hypochlorite with concentrated HCl:ClO- + H+ + Cl- = OH- + Cl2 = faulty: prepared alkali acid
(5) ignore a substance of anions and cations in proportion.
Such as: H2SO4 Ba (OH) solution into 2 solution: Ba2+OH-H+SO42- = BaSO4: H2O
Right: Ba2+2OH-2H+SO42- = BaSO4: 2H2O
(6) "=" "" "=" "down" the improper use of symbols
Such as: Al3+ + 3H2O = Al + 3 (OH): 3H+ note: salt hydrolysis is generally reversible, Al (OH) 3 less, so it can not play down ""
2. ions to determine, you must pay attention to the additional conditions given in the problem.
The acidic solution (H +), alkaline solution (OH-), and the solution can emit flammable gas in the water by adding aluminum powder after the ionization of H + or OH-=1 * 10-amol/L (a>7
or a<7) solution.
The nonferrous ions MnO4-, Fe3+, Fe2+, Cu2+, Fe (SCN) 2+. The MnO4- NO3- has strong oxidation in acidic conditions.
The S2O32- occurred in the acidic conditions of redox reaction: S2O32-+2H+=S: +SO2 = +H2O
The problems require "some quantity coexist" or "may be a lot of coexistence"; "not a coexistence" or "must not be a lot of coexistence".
It is with the title and set the conditions and requirements, such as "excessive" and "small", "moderate", "amount of substance", "arbitrary" and the order of adding reagents on the effect of the reaction etc..
Ten, the seven principles of middle school chemistry experiment operation
1., "from the bottom up" principle.
2., "left to right" principle.
3., first "plug" after the "set" principle.
4., "solid first release" principle, "liquid plus" principle.
5. principle of prior tightness (before loading).
6. after the point of alcohol lamp (all devices installed after the point of alcohol lamp) principle.
7., connecting catheter ventilation is a principle of short growth.
Eleven, the storage and use of special reagents in 10 cases
1.Na, K: isolation of air; oxidation resistance; preservation in kerosene (or liquid paraffin); (Li sealed in paraffin). Take tweezers, slide on the cutting, filter paper to absorb kerosene, and then put the remaining part of kerosene.
2.: the preservation of white phosphorus oxidation in the water, cool, dark. Remove the tweezers and put them into the water immediately. Cut with the long handled knife and blot the water with the filter paper.
3. liquid Br2: toxic, volatile, in the mouth of the mouth of
a small bottle, and sealed with water. Tight bottle top.
4.I2: Yi Shenghua, and has a strong pungent odor, should be kept in a wax sealed bottle, placed at low temperature.
5. thick HNO3, AgNO3: see light decompose easily, should preserve in brown bottle, put in low temperature, avoid the place of light.
6. solid caustic soda: easy to tide solution, easy to seal the use of dry large mouth bottles to preserve. The bottle with a rubber plug tightly or with plastic lid tightly.
7.NH3 H2O: volatile, should be sealed at low temperature.
8.C6H6, C6H5 - CH3, CH3CH2OH, CH3CH2OCH2CH3: volatile and flammable, should be sealed storage at low temperature, and away from the fire.
Nine
Fe2+ salt solution, H2SO3 and its salt solution, hydrogen sulfate and its salt solution: because it is easy to be oxidized by air and should not be placed for a long time, should be used now.
10. brine, lime water, silver ammonia solution, Cu (OH) 2 suspension, all with the distribution with the use of not placing a long time.。