【判断题】加成反应中,试剂分成两部分同时加到双键的两端。
【单选题】Ultraviolet light of wavelength 350 nm and intensity 1.00 W/m 2 is directed at a potassium surface. The maximum kinetic energy of the photoelectrons is ( )
【单选题】Consider: radio waves (r), visible light (v), infrared light (i), x-rays (x), and ultraviolet light (u). In order of increasing frequency, they are:
【单选题】The gas present in the stratosphere which filters out some of the sun's ultraviolet light and provides an effective shield against radiation damage to living things is
【简答题】有份CIF合同,出售矿砂5 000公吨,合同装运条款规定:“CIFHamburg,1999年2月份,由一船或数船装运。”买方于2月15日装运了3 100公吨,余数又在3月1日装上另一艘轮船。当卖方凭单据向买方要求付款时,买方以第二批货物延期装运为由,拒绝接受全部单据,并拒付全部货款,卖方提出异议,认为买方无权拒收全部货物。你认为应如何处理?
【判断题】In spite of many risks, scientists will finally build an environment without ultraviolet light in space suitable for humans to live.
【判断题】加成反应中,试剂的两部分同时加到双键的两端。( )