题干

工业制硫酸中的一步重要反应是SO2在400-500℃下的催化氧化:2SO2+O2=2SO3,这是一个正反应放热的可逆反应。如果反应在密闭容器中进行,下述有关说法中错误的是(    )

A:使用催化剂是为了加快反应速率,提高生产效率

B:在上述条件下,SO2不可能100%转化为SO3

C:为了提高SO2的转化率,应适当提高O2的浓度

D:达到平衡时,SO2的浓度与SO3的浓度相等

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答案(点此获取答案解析)

D

同类题3

   DIY, which means Do It Yourself, is quite popular in UK. Lots of stores and supermarkets sell DIY things. TV programs show people how to DIY.
   English people like DIY. There is a saying in UK---“An Englishman’s home is his castle”. Huge numbers of people spend their holidays making their homes beautiful “castles”. If there is anything that needs fixing around their houses, such as painting the walls or putting in a new shower, they will do the jobs themselves. They share DIY experiences with their friends. More and more people have discovered the joy of DIY. Sometimes people also DIY for saving money. With the economic downturn at present, many people can not afford to buy a bigger house. They are looking at how they can make their houses better without spending a lot of money. It is not surprising that DIY is so popular.
   DIY can be difficult. There is a huge market for DIY furniture which people need to put together themselves with a few basic(基本的) tools (工具). However, people often find it not easy to build a piece of furniture because they can’t understand the instructions. Sometimes the instructions are simple and clear, but the furniture itself is difficult to build. One thing is for sure, though most DIY projects are started with the best intentions (目的,意图), many of them may not get finished. DIY can also be dangerous. For example, anything electrical should be done by a professional worker. Unluckily, many people don’t care about this warning and put themselves in danger. It is reported that in just one year over 230 000 people were hurt while doing DIY in UK, including 41 000 who fell off ladders (梯子).
Therefore, DIY can bring us fun and help us save money, but it is not always as easy as it is thought to be if we bite off more than we can chew. Maybe factories should make products that are easier and safer for us to DIY.