二氧化碳 英语版 .ppt

carbon dioxide symbol :co2 New words density [densiti] n. 密度 property [prɔpəti] n.性质 spray [sprei] v.喷射 beaker [‘bi:kə] n. 烧杯 acidic [əsidik] adj. 酸的，酸性 purple litmus [‘litməs] solution 紫色石蕊试剂 squash[skwɔʃ] vt. 压制，压扁 carbon dioxide Physical properties State Color and smell Dissolvability Density Chemical properties carbon dioxide Physical properties State: gas Color：no color Smell：no smell Experiment 1 phenomena plastic bottle is squashed to prove the pressure in the bottle reduced ,so co2 can dissolve （溶解）in water phenomena the two bags do not balance to prove co2 has a higher density than air Experiment 2 carbon dioxide Dissolvability：soluble （溶解） in water Density：has a higher density than air Experiment 3 phenomena the purple flower turn red to prove a acidic gas(酸性气体） Experiment 4 phenomena the candle on the lower step goes out first to prove co2 does not help burning co2 has a bigger density than air(phycical property) carbon dioxide Chemical properties: a acidic gas does not help burning Carbon dioxide Physical properties: State: gas Color：no color Smell：no smell desity:higer than air can dissove in water Chemical properties: a acidic gas does not help burning A exercise: The following statement，which is the correct answer（ ） A. CO2 can dissolve in water，and can make drink B.CO2 can dissolve in water which is a physical change C.H2CO3 (carbonic acid ) is so stable that it is hard to break down D.CO2 can make purple litmus solution turn colorless homework:to prepare a lesson about other chemical properties of co2 See you !