题干

填写实验报告。

实 验 内 容

实 验 现 象

分析、结论及解释

①测定碱溶液的pH

取两片pH试纸,放在白瓷板上,分别用玻璃棒蘸取稀氢氧化钠溶液、澄清石灰水,再分别滴到pH试纸上,将试纸显示的颜色与____比较,读出pH。


若实验过程中,用沾有水的玻璃棒蘸取溶液,则所测得的pH____(填“>”、“=”或“<” )实际值。

②碱和指示剂作用

取两支洁净的试管,分别加入约2mL的稀氢氧化钠溶液、澄清石灰水,再分别加入3滴无色酚酞溶液,观察溶液颜色变化。

两支试管中的酚酞溶液均变为        色。

稀氢氧化钠溶液、澄清石灰水都呈_____性。

③碱和非金属氧化物的反应

用排水法收集一瓶呼出的气体,然后加入约2mL澄清石灰水,振荡,观察现象。

澄清石灰水变浑浊。

反应的化学方程式:____

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答案(点此获取答案解析)

标准比色卡,<,碱性,CO2+Ca(OH)2 = CaCO3↓+ H2O

同类题4

任务型阅读

    Weight loss is a hard topic. Lots of people aren't satisfied with their present weight, but most people aren't sure how to change it. You may want to look like the models or actors in magazines or on TV, but those goals might not be healthy or realistic for you.____

    So what should you do about your weight control?

    ____The best way to find out if you are at a healthy weight or if you need to lose or gain weight is to talk to a doctor or dietitian(营养学家)____ If it turns out that you can benefit from weight loss then you can follow a few of the simple suggestions listed below to get started.

    ____People who lose weight quickly by crash(速成的)dieting or other extreme measures usually gain back all of the pounds they lost, because they haven't permanently changed their habits. Therefore, the best weight management ways are those that you can maintain for a lifetime.

    Small changes are a lot easier to stick with than large ones. Try reducing the size of what you eat.____ Once you have that down, start gradually introducing healthier foods and exercise into your life.

    It's a good idea to maintain a healthy weight because it's just that: healthy.

A. Try giving up regular soda for a week

B. Try to pay attention as you eat and stop when you're full.

C. Weight management is about long-term success.

D. Besides, no magical diet will make you look like someone else.

E. Being healthy is really about being at a weight that is right for you.

F. Changing from whole to nonfat or low-fat milk is also a good idea.

G. They will compare your weight with healthy standards and help you set goals.