题干

下列所设计的鉴定方案或者结论正确的是(      )

A:检验C2H5Cl中的氯元素时,将C2H5Cl和NaOH溶液混合加热后,加入稀硫酸后进行酸化,再加硝酸银溶液

B:向溶液中加入盐酸,有无色气体逸出,此气体能使澄清石灰水变浑浊,则该溶液中含有CO32-

C:向0.1mol·L1 FeSO4溶液中滴加少量酸性KMnO4溶液,KMnO4溶液褪色,说明Fe2+具有氧化性

D:向2.0mL浓度均为0.1mol·L1的KCl、KI混合溶液中滴加1~2滴0.01mol·L1 AgNO3溶液,振荡,沉淀呈黄色,说明AgCl 的Ksp比AgI 的Ksp大

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D

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    A new phone app uses shaking from smartphones to warn people about earthquakes. The new app is called MyShake, which is the work of four researchers at the University of California. Berkeley.

    Smartphones are equipped with accelerometers(加速器). MyShake uses phone accelerometers to measure seismic (地震的) activity. It has been programmed to know the difference between normal activity and earthquake movement. The software developers say their app is right 93 percent of the time. A smartphone sends seismic information to the app developers. If the developers receive several warnings from one area, it recognizes that an earthquake may be taking place or will take place soon. Using information sent from the app, the network then judges the location and strength of the quake in real time. MyShake can record 5.0 earthquake at distances of 10 kilometers or less.

    MyShake uses very little power, according to its developers. Only when seismic activity is sensed by the app does it become active and sends data to the network. The app works best when your phone is resting on a flat surface, like a table.

    The developers hope that MyShake can add to information collected by the U.S Geological Survey. That U.S agency has created the Earthquake Early Warning System, also known as the EEW. The EEW has used sensors for measuring quakes in many areas. In places where no such equipment exists, MyShake may be the only method of early quake detection (发现). The app also shows ways to stay safer during an earthquake. The developers say it will become more effective as more people use it.

    The developers say they hope to add a feature that will warn people about possible tsunami after an earthquake.