【简答题】乙酰水杨酸即阿斯匹林(aspirin),是19世纪末合成成功的,作为一个有效的解热止痛、治疗感冒的药物,至今仍广泛使用,有关报道表明,人们正在发现它的某些新功能。阿斯匹林是由水杨酸(邻羟基苯甲酸)与醋酸酐进行酯化反应而得的,装置如图所示 主要试剂和产品的物理常数 根据上述信息回答下列问题 (1)制取过程中所用乙酸酐要使用新蒸馏的乙酸酐,分析可能原因:___________________ (2)步...
【简答题】阅读理解。 February has long been a month of romance. With the sweet smell of roses in the air, romantic films hit cinemas and love stories fill newspapers and magazines. On the 14th day, it is a custom fo...
【单选题】HXN5水冷却系统共有2种工作模式,一个是热机模式,另一个是()
【单选题】( )窗体是独占式的,即退出窗体之前不能对其他对象进行操作。
【简答题】阅读理解。 Although Paris is often considered the city of romance, close to a million s who call it home are single. Many single people say that France's capital is one of the most difficult places to...
【简答题】三、阅读理解(40%) A February has long been a month of romance. With the sweet smell of roses in the air, romantic films hit cinemas and love stories fill newspapers and magazines. On the 14th day, it is a c...