化学与生产、生活密切相关，下列有关说法不正确的是 A. 用浸泡过高锰酸钾溶液的硅藻土吸收水果产生的乙烯以达到保鲜要求 B. 高纯度的二氧化硅广泛
（09年山东实验中学诊断三理）在等比数列中，若，则的值为 A．9 B．1 C．2 D．3
People in Yancheng are proud of ________ they have achieved in the past thirty years. A. how B. which C. what D. when
下列条件下的氯化氢气体的溶液即为盐酸，其溶质的质量分数最大的是 ( ) A.20 ℃的饱和溶液 B.20℃的不饱和溶液 C.80
Florida is celebrating a big anniversary this year. Five hundred years ago, on April 2, 1513, Spanish explorer Juan Ponce arrived on the east coast of what is now Florida. Native Americans had been
With the introduction of family planning policies in the 1970s, most Chinese teenagers have no brothers or sisters．They get to be the beloved（心爱的）__21__child．But they may not realize tha
下列事实可以证明一水合氨是弱电解质的是( ) ①0.1 mol/L的氨水可以使酚酞溶液变红 ②0.1 mol/L的氯化铵溶液的pH约为5 ③在相同条件下，
如图所示，金属棒MN水平放置与两根竖直平行金属导轨接触，且可无摩擦下滑，导轨间接有一阻值为R的电阻，导轨间有一匀强磁场垂直于导轨平面，金
