题干

有2份质量分数不同的NaHCO3和NaOH的混合物,将它们分别用酒精灯隔绝空气加热至恒重并排除气体后恢复到常温,测得的数据如下:则下列叙述不正确的是
 
第一份
第二份
 混合物的质量(g)
9.2
20.8
 反应后固体的质量(g)
8.3
15.9
 

A:第二份得到的是纯净物

B:第一份混合物中NaOH的质量分数更大

C:根据表中数据不能计算出第一份混合物中NaHCO3的质量分数

D:第二份混合物中NaOH的物质的量小于NaHCO3的物质的量

上一题 下一题 0.0难度 选择题 更新时间:2017-05-04 04:14:10

答案(点此获取答案解析)

C

同类题3

阅读理解

    Sometimes it is difficult to talk to taxi drivers. They must give all their attention to the road as they work out the shortest way to the place where you are going. However, passengers from Wangfujing were in surprise when they took a taxi. The driver just would not stop talking in English.

    Organized by the Cultural and Education Section of the British Embassy, “Dare to Speak” examines if Chinese people will speak English in “real-life” situations.

    Matthew Knowles, an acting student from South Carolina at Beijing Film Academy, acted the part as the “driver”. He collected six passengers on Saturday morning, most of whom were female white-collar (白领)workers.

    “Of course they were surprised at first, wondering why I'm driving a taxi, and wondering whether this is a real taxi, but then most of them were pretty willing to speak,” he said. Knowles said he was also surprised by his “passengers”. “Apart from my first ‘passenger', who could speak very little English, all the rest spoke English very well, and it was fun to communicate with them,” he said, adding that some “passengers” were quite talkative.

    The “foreign taxi driver” project was just one of the “Dare to Speak” activities, which have been going on since the end of October. Other projects included a foreign store owner near a high school in Beijing, a cook in a Shanghai university canteen. They were testing the willingness of Chinese people, especially students and white-collar workers, to speak to foreigners in English.

    Rong Xin, senior manager of IELTS (雅思) with the British Embassy, said they hoped to let IELTS takers in China know that communication is the ultimate goal of IELTS.

    “We hope that more and more IELTS takers in China can realize the importance of communicating in English in real life, instead of just getting high test scores,” she said.