题干

下列有关溶液的说法中正确的是(   )

A:同种溶质的饱和溶液一定比它的不饱和溶液的溶质质量分数大

B:饱和溶液转化为不饱和溶液,溶液的质量一定增大

C:饱和溶液恒温蒸发部分溶剂后,溶质的质量分数一定不变

D:不饱和溶液转化为饱和溶液,溶质的质量分数一定变大

上一题 下一题 0.0难度 选择题 更新时间:2019-09-19 10:44:03

答案(点此获取答案解析)

C

同类题1

阅读理解

    China is fully prepared to export a full supply chain of high-speed railway technology, according to industry experts.

    China Railway Corp, the national rail operator, said exports of railway equipment and railway construction projects are proceeding well, and breakthroughs are being made in a number of projects overseas.

    Among the projects, the first full-chain commission, the Jakarta to Bandung high-speed railway in Indonesia, which includes technology, design, construction, equipment manufacture, supply of resources, operations management and staff training, has been granted a construction permit and work is proceeding smoothly.

    “China's railways have established a comprehensive and advanced technology system, which is able to provide overseas customers with solutions from many different perspectives, including financing, construction, operations, and research and development,” said Yang Zhongmin, the CRC's deputy chief engineer, who added that China's railway system is competitive in terms of technology and economy of use.

    According to Yang, the nation's railway equipment and infrastructure (基础设施) service businesses have entered markets in Asia, Europe, North America and Africa.

    Last year, Joko Widodo, president of Indonesia, and Malaysian Prime Minister Najib Razak, rode Chinese-made bullet trains.

    Yang Hao, a professor of rail transportation management at Beijing Jiaotong University, said China has a major advantage in that it is able to export a full range of railway technology: “For example, it is inconvenient to import the technology for the signaling system from one country and civil engineering technology from another.”