20℃的水（密度为1000 https://img0.ph.... 。
举一反三
- 水的密度为1000 ，2L水的质量和重量是多少？
- 如图所示，离心机通风机借集流器从大气中吸入空气。若插入盛水容器的玻璃管中的水上升高度为h，则通风机流量<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/b90be52d519d4880a560e59df52dd29c.png" />=（）。<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/dca2260bbd5c4051b28bbb87ae1d6de9.png" /> A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/7b4225635cfe41e28af202418785be8d.png" border="0" vspace="0" /> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/05404534275442c597194a44ee9f46f7.png" border="0" vspace="0" /> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/5509cc1799e54c64a7a11a7f37417710.png" border="0" vspace="0" /> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/307ded8ddb2c486d935b6bc79faa7688.png" border="0" vspace="0" />
- 我国常用的石油相对密度指的是t℃时油品密度与（）水密度之比。 A: 0℃ B: 15．6℃ C: 4℃ D: 20℃
- pH = 14 时，水作为氧化剂的半反应是（ ）。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202008/94b9c5788d7141cea3a173c90e1b1246.png" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202008/4d674f36cf1741e69c88a612d06ab630.png" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202008/e170f545fd6c4396899446c62a36d73a.png" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202008/f20ab184ab6b41cca40ea30293b44ca1.png" />
- 一个横放着的圆柱形水桶，桶内放有半桶水。设桶的底半经为<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202108/03b53e3b35124e96977be0fd2695dedd.png" />，水的密度为<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202108/dd0c6d1b299144929340fb6701f6fbfb.png" />，则桶的一个端面上所受的压力为<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202108/7cfd44f6645b436aa24ee21353a1076e.png" /> （ ）