题干

为符合绿色化学的要求,某研究性学习小组进行如下设计:

第一组:以空气为氧化剂法

方案1:将铜粉在坩埚中反复灼烧,与空气充分反应生成氧化铜,再将氧化铜与稀硫酸反应.

方案2:将空气或氧气直接通入铜粉与稀硫酸的混合物中,向反应液中加FeSO4或Fe2(SO4)3,即发生反应.反应完全后加CuCO3调节pH到3~4,产生Fe(OH)3沉淀,过滤、蒸发、结晶得CuSO4•5H2O.滤渣可循环使用.

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    It's just been three months after the first bike-sharing company arrived in Singapore, but reports of abuse and vandalism(故意破坏)of shared bikes in the city keep appearing on social media.

    The majority of these shared bikes are stationless, which means they don't need to be stopped at a designated(指定的)spot. They lock themselves after your ride is over, and you're meant to just leave the bike at the side of a road.

    But users have been chaining up bicycles outside their apartments, preventing others from using them. Some people bring them up to their apartment floors, so they can't be found easily by other users. Some people have removed the bikes' number plates or codes, and some even have painted over the bikes to claim the bikes for themselves. Most of the abused bikes belong to either Singapore-based oBike, or ofo, a bike-sharing giant based in China.

    ofo has encouraged Singaporean users to report issues. oBike said that the number of bicycles that were damaged made up less than one percent of its fleet. The company said in February that it planned to bring in “tens of thousands” of bikes by mid-2017. The company has yet to ban anyone from its service, but said that it would take appropriate action – including making reports to the police.

    oBike also introduced a shortcoming system, similar to that of its competitor, China-based Mobike. Users start with 100 points, which get taken away for errant(出格的)behaviour such as forgetting to lock the bike, or parking at non-designated areas. Users are banned from using oBike when their scores reach zero. oBike has an eight-man operation team that can remove bicycles parked casually.

    When approached for comment, Mobike said, “In China, just as in Singapore, there are always a tiny minority of people who abuse the bikes, so we designed our system to prevent this type of abuse.”