题目

下列说法正确的是( ) A．BaSO4难溶于水，其水溶液导电能力极弱，所以BaSO4是弱电解质 B．NH3溶于水得到的溶液能导电，所以NH3是电解质 C．强电解质溶液的导电能力不一定比弱电解质溶液的导电能力强 D．导电能力强的溶液一定是强电解质溶液 答案：解析：选C BaSO4是强电解质，电解质的强弱与其溶解性无关，也与其溶液的导电能力无关。溶液的导电能力强弱与溶液中自由移动的离子的浓度以及离子所带的电荷数有关，与电解质的强弱无关。溶于水能导电的物质不一定是电解质，NH3溶于水能导电是因为其与水反应生成的NH3·H2O电离的结果，NH3自身不29、 Visit the Skywalk at Grand Canyon West Today! For Booking Call: 1-866-944-7263 Package Fee: ＄289 Per Adult;  ＄274 Per Child  All Fee’s Included.    NO Hidden Cost.              Book Now!        Experience the newly opened Grand Canyon（大峡谷）West Skywalk in Colorado．Departing （离开） from Grand Canyon’s South Rim by Airplane to Grand Canyon’s West Rim, you will land and take a ground tour to the Skywalk! Walk on air for 70 feet over the edge of Grand Canyon West．        This Skywalk has been open since March 28, 2007．Daily visitor-ship to the Skywalk has been over 4,000 people．Please be patient to enjoy your moment on the Skywalk．        After you have experienced the one and only Grand Canyon Skywalk Glass Bridge, you will return to the Grand Canyon West Airport and take your Airplane for a flight back to the South Rim of the Canyon．This is a tour never to be forgotten as you will have walked on air over the Grand Canyon． Tour Itinerary （行程） Tour Duration 5.7 Hours The Grand Canyon Adventure Skywalk Flight from Grand Canyon South Rim to Grand Canyon West 1 Hour Experience a bird’s-eye view of the Grand Canyon as you make your way to Grand Canyon West． Light Lunch at Guano Point at Grand Canyon West 2 Hours You’ll be taken by bus to Guano Point with breathtaking views of the western part of the Grand Canyon where the Colorado River makes its way into Lake Mood．Every table for lunch has a view． Walk on the World Famous Skywalk 1.5 Hours Finally you’ll board your bus to Eagle Point, home of the Grand Canyon Skywalk．Now it is time for you to walk on air for 70 feet over the Grand Canyon． Flight Back to Grand Canyon South Rim 1.2 Hours After time on the Skywalk, you’ll return to the Grand Canyon West Airport and return to Grand Canyon South Rim in time for dinner and sunset． 1．This advertisement is for __________．      A．Grand Canyon West                             B．Grand Canyon South      C．Grand Canyon                                     D．the Skywalk 2．The package fee does NOT cover the cost of _______． 3．The Grand Canyon Skywalk Bridge is made of glass because ______．      A．it looks stranger                                   B．it is cheaper to build      C．it looks more beautiful                          D．it gives you a better view 4．According to the Tour Itinerary, the route is ______．      A．South Rim→Guano Point→West Airport→Eagle Point→West Airport→South Rim      B．South Rim→West Airport→Guano Point→Eagle Point→West Airport→South Rim      C．South Rim→West Airport→Eagle Point→Guano Point→West Airport→South Rim      D．South Rim→West Airport→Eagle Point→West Airport→Guano Point→South Rim