题干

固定容积为2L的密闭容器中发生反应xA(g)+yB(g)⇌zC(g),图I表示t℃时容器中各物质的量随时间的变化关系,图II表示平衡常数K随温度变化的关系.结合图象判断,下列结论正确的是(   )

A:该反应可表示为:2A(g)+B(g)⇌C(g)△H<0

B:t℃时该反应的平衡常数K=6.25

C:当容器中气体密度不再变化时,该反应达到平衡状态

D:t℃,在第6 min时再向体系中充入0.4 mol C,再次达到平衡时C的体积分数大于0.25

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D

同类题3

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    More companies and recyclers are taking steps to ensure that old electronic devices such as TVs and computers aren't sent to poor countries.

    The Basel Action Network, a Seattle-based non-profit that largely exposed the overseas discarding (丢弃) of US electronic waste, on Thursday launched a programme to use third-party employees to certify (证实) recyclers who don't export dangerous electronic waste.

    The so-called e-Steward recyclers will also agree not to discard the waste in US landfills and agree to meet other criteria. The certification is intended to provide companies and consumers with some assurance that the waste, which can include toxins (毒素) such as lead and mercury, is disposed of safely.

    The Government Accountability Office, in a 2008 report, declared that US electronic waste was often disposed of unsafely in such countries as India. There, workers recycle gold, silver and copper from the waste, often in open-air acid baths.

    The Basel Network also says it won assurances from 13 organizations, including Samsung, Bank of America, Wells Far-go, that they'll use e-Steward recyclers whenever possible. Wells Fargo had already been using recyclers who declared not to export. So far, Basel has certified three recyclers and seven sites.

    Before e-stewards, even, companies that wanted to avoid export of electronic waste had to “hope for the best”, when, they handed their waste to recyclers, says Robert Houghton, president of Ohio-based recycler Redemtech. It is an e-Steward that counts major companies among its customers. “Now, they can get some proof,” Houghton says.

    Basel's standards compete with another set launched in January. It was made by industry and backed by the Environmental Protection Agency.

    That standard, called R-2, doesn't ban the export of dangerous electronic waste but requires that it be handled safely. Instead of a ban, the Institute of Scrap Recycling Industries says, efforts should be made to help poor countries develop safe recycling.

同类题4

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    When I was ten years old I went to the USA to visit some family friends. I noticed something funny about the way everyone spoke English.

    One moment! I remember very clearly was at the beginning of the holiday, when my friend asked me if I wanted to order “French fries”. I couldn't imagine what they were. She was amazed that I had never tried them and she ordered a portion for us to share. When the waiter brought us some chips, I asked her where the French fries were. She pointed at the plate of chips! Later that week she said she was going to buy some “chips” from the supermarket. She came out with a packet of crisps(薯片)! How come?

    During that holiday we were also offered “biscuits” with our lunch. This was a very strange idea to me, because in England biscuits are sweet. I later realized that “biscuits” in America are salty snacks. What we call “biscuits', they call “cookies”.

    I was also embarrassed when a stranger told me she liked my “pants”. I wondered how she could see them! My mum then told me that they call “pants” what we call “trousers”, the outer clothing that you wear on your legs instead of inside clothing!

    I was disgusted when I saw an “eggplant” pizza on the menu in a restaurant. But I was puzzled how eggs can grow on plants. My dad ordered this pizza and it was covered in aubergines(茄子). “They call aubergines 'eggplant' in America!” he told me.

    I think part of the excitement of learning a language is learning about the differences that exist in how it is spoken in different places.