常见物质的性质与变化（Properties and changes of common substances）Topic two properties and changes of common substancesMeasurement and control navigation tableKnowledge pointThe questions and difficultyMaterial properties1,5,11Properties and changes of water and solution2,8 (middle)Air compositionThreeProperties of metals4,9 (middle)Acids, bases, salts6,13,17 (middle), 18 (middle)Changes and properties of matter7,10 (middle), 12,15,16 (middle)Material change typeFourteenFirst, the multiple-choice question1. (2011 Guangxi Guilin) is a plastic plasticizer softener, banned from being added in food. The following properties of plasticizers are chemical properties (C)A. colorless viscous liquidB. melting point -50 DEG CC. has chronic toxicityD. is soluble in most organic solvents2. (2011 Anhui Chaohu version) World Water Day March 22, 2011 theme is city water: responding to the urban challenge. The following statement about water is wrong (A)A. water pollution has nothing to do with human activitiesB. the water in nature is not pure waterC. tap water can be sterilized by adding chlorine gasD. the available fresh water resources on the earth are limited3. (2011 Sichuan, Dazhou) Dazhou May 20, 2011 air quality report: Old City air pollution index was 64, air quality class II, the air quality is good, the main pollutant in the air is respirable particulate matter. The following statement about the elements of air is correct (B)A. oxygen is chemically active and belongs to fuelB. nitrogen is not chemically active and can be used for food preservationThe greater the air quality level listed in the C. air quality report, the better the air qualityD. carbon dioxide in the air content increases, will cause greenhouse effect, belonging to air pollutantsAnalysis: oxygen belongs to combustion support, A wrong; air quality report listed in the air quality level is smaller, the air quality is better, C wrong; carbon dioxide can cause greenhouse effect, but not air pollutants, D wrong.4. (2011 Anhui Chaohu) Wuhu iron picture is an exotic flower in the garden of Arts and crafts China. It is made of steel as main material and made by multi - process such as forging, welding, pickling and painting. Which of the following statements is not true about the iron (D)A. painting should be hung in a dry environment.The rust on the material used in B. can be cleaned with dilute hydrochloric acidC. to make painting Tiehua molding is beautiful and can rustThe main material used in D., low carbon steel, has better forging properties. It does not belong to ferrous alloysAnalysis: A, C option approach can prevent iron rust, correct; B reaction for Fe2O3+6HCl2FeCl3+3H2O, right; low carbon steel belongs to iron alloy, D option error.5. (2011 Anhui) a method of reasoning commonly used in scientific inquiry. According to the following experimental facts, the conclusion is correct (C)numberExperimental factsempirical conclusionAA solution to phenolphthalein solution turns redThe solution must be NaOH solutionBA substance can conduct electricityThe substance must be a metallic substanceCDetermination of temperature at room temperaturePH=3 of solutionThe solution must be acidicDA gas does not carry a bandMars bars againThe gas must have no oxygenAnalysis: make red phenolphthalein solution is alkaline solution, is not necessarily the solution of NaOH, A and part of the solution can be wrong; graphite conductive metals, but not B, wrong; if a gas can make Mars with wood again, may also be the oxygen purity is not high enough, D.6. (Guangdong, Zhaoqing, 2011) the following solutions are colorless and can coexist in large amounts at pH=1 (C)A.CuSO4 NaCl KNO3B.NaOH NaCl NaNO3C.Na2SO4 NH4Cl ZnCl2D.K2SO4 AgNO3 NaClAnalysis: when pH=1, H+ exists in the solution. In the case of H+: A can coexist, but CuSO4 solution is blue; NaOH does not coexist with H+ in B; AgNO3 does not coexist with NaCl in D; no precipitation in C, gas and water can coexist.7. (2011, Sichuan, Yaan) through junior high school chemistry study, we can sum up or find a lot of knowledge with a certain regularity. In the following description of the law, the correct one is (C)A. carbon is a large family, all of which contain carbonB. all acids must contain oxygenWhen the C. metal reacts with the acid, the quality of the solution increasesD. acid, alkali and salt can react with each otherAnalysis: some substances do not contain carbon, A error; all acids are contained in hydrogen, but not necessarily contains oxygen, B error; metal and acid replacement reaction after heavy metals into solution, hydrogen is replaced, solution quality are increased, C can correct; double decomposition reaction between acid and alkali, s