题干

请根据下列图示回答问题:①甲图中R物质在室温(20℃)时的饱和状态为D点,40℃时的饱和状态为A点,现将  甲图中的R溶液从A状态变到B状态,请设计并简述一个简单的实验操作途径:____

②乙图是表示M,N两种物质饱和溶液的溶质质量分数随温度变化的曲线.现分别向60g M,80g N固体中各加入150g水,并加热至完全溶解,同时各蒸发掉50g水,冷却至t℃,下列分析正确的是____(填序号).

a.只有N析出晶体  b.M,N两种溶液的溶质质量分数相等  c.只有M析出晶体

d.M,N均有晶体析出  e.M,N两种物质的溶解度相同.

上一题 下一题 0.0难度 选择题 更新时间:2016-05-10 12:38:29

答案(点此获取答案解析)

可先将R溶液从A状态稀释到C状态,再将温度升高到60℃,bde

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Canada Day

                                                                  

                                                                                                                              

      Since 1982, July 1st has been officially known as Canada Day. Canadians of all ages take part in this festival across the country.
  Canada Day is the year's biggest national party. In many towns and cities, the government organizes a lot of events, often outdoors. These include parades(游行), concerts, festivals, firework displays and ceremonies for new Canadian citizens(公民). The celebrations often have a patriotic mood. Canada's national flag, a symbol for Canada Day, can be seen everywhere and a lot of people paint their faces red and white, which are Canada's national colors. The celebrations in Ottawa, Canada's capital city, are especially grand and exciting.
  In the province of Quebec, many home rentals(租赁)start on July 1st and last for exactly one year, and many people in Quebec spend Canada Day moving from one house to another. So in Quebec, Canada Day is also known as Moving Day.
  Many organizations, businesses and stores are closed this day. Only some bookstores, ho spitals and gas stations may be open. Post offices are closed, too. As Canada Day falls in the Canadian summer holiday period, all schools are closed as well. In some areas, special services are provided for large events. The concerts, parades and festivals may cause some traffic jams.