用天平和量筒测定盐水的密度,有如下操作: (A)用天平称出烧杯和盐水的总质量M;

题型:实验题

问题:

用天平和量筒测定盐水的密度,有如下操作:

(A)用天平称出烧杯和盐水的总质量M;

(B)用天平称出烧杯和剩下盐水的总质量m;

(C)调节天平使天平平衡;

(D)将烧杯中的盐水倒入量筒中一部分,记下量筒中盐水体积V;

(E)用公式ρ=(M-m)/V计算出盐水的密度。

那么,正确操作步骤的序号应是____________________。

考点:液体密度的测量
题型:实验题

根据短文内容,回答问题。

     My name is Jane Brown. I live in Manchester, 77 Victoria Drive. I haven't got a telephone, but you

can phone my next-door neighbor, Mrs. Johnson. Her number is 246-8021.

     I left school five years ago. I was good at maths at school. That was my best subject. I wasn't very

good at English. Art was my worst subject.

     I like swimming and dancing. I play tennis every weekend if I can. I'm very fond of music. My favorite

composer is Beethoven (贝多芬). I like pop, too. Foreign languages? Well, I learned French at school.

I was quite good at it. I can understand quite well and speak a little.

     After I left school, I worked on a farm for a year. Then, I worked in factory for six months. I didn't

like it. I'm working as a waitress at the moment. I want to get a job in a big company.

1. Does Jane Brown have a telephone?

    ____________________________

2. Which subject did she do better, English or maths?

    ____________________________

3. Can she speak French very well?

    ____________________________

4. How often does she play tennis?

    ____________________________

5. Where is she working now?

    ____________________________

题型:实验题

如图所示是体温计,它的最小分度值为______℃,此时体温计的示数为______℃.在“测定物质的密度”实验中,所用的托盘天平如图所示.实验时,应先向______调节平衡螺母(选填“左”或“右”),直到天平的横梁在水平位置平衡.称量物体质量时,被测物体应放在天平的______盘(选填“左”或“右”),然后通过加减砝码或______,使天平横梁再次回到水平位置平衡.

题型:实验题

我国人口多、耕地少,为解决粮食问题,必须[ ]

A.减少经济作物播种面积,增加粮食作物播种面积

B.增加开垦荒地,以增加粮食产量

C.开垦草原,扩大粮食作物播种面积

D.坚持走科教兴国的道路,提高农业生产力

题型:实验题

一个企业的领导者直接管理几个部门的控制系统的沟通形式为()

A.环式 

B.Y式 

C.轮式 

D.全通道式 

题型:实验题

当设备已有施工图纸,在安装现场制作的非标准设备,其合同价格应按()确定。

A.成本计算估价法

B.按结构分部组合估价法

C.定额估价法

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