试题与答案

能证明“CaCO3并非绝对不溶于水”的实验事实是() A.向少许CaCO3粉末加

题型:选择题

题目:

能证明“CaCO3并非绝对不溶于水”的实验事实是(   )

A.向少许CaCO3粉末加人NaOH溶液充分振荡.无明显现象

B.向少许CaCO3粉末加入过量稀盐酸充分振荡,粉末消失且有气泡产生

C.向2颗蚕豆粒般石灰石固体加人3mL.蒸馏水,滴人酚酞试液片刻内不变红

D.向少许CaCO3粉末加人3mL.蒸馏水充分振荡.滴入酚酞试液即变红

答案:

答案:D

本题考查同学们灵活运用所学知识、化学实验方案设计与评价的能力,掌握碳酸钙的性质是正确解题的关键。A、CaCO3不与NaOH溶液反应,向CaCO3粉末加人NaOH溶液充分振荡,无明显现象,不能证明“CaCO3并非绝对不溶于水”; B、CaCO3能与稀盐酸反应,向少许CaCO3粉末加入过量稀盐酸充分振荡,粉末消失且有气泡产生,与CaCO3是否溶于水无关,不能证明“CaCO3并非绝对不溶于水”; C、由于石灰石固体与水接触面积小,即使能溶于水,片刻内溶解的量也很少,故加人3mL蒸馏水,滴人酚酞试液片刻内不变红,不能证明“CaCO3并非绝对不溶于水”; D、水显中性,不能使酚酞试液变红;向少许CaCO3粉末加人3mL蒸馏水充分振荡,滴入酚酞试液即变红,说明是碳酸钙粉末溶于水显碱性,能证明“CaCO3并非绝对不溶于水”,故选D。

试题推荐
题型:阅读理解

If you are living in the city, have you ever thought of going to live in the country for a change? Many people want to move from the country to the city because they think life in the city is more exciting and better than that in rural (农村的) areas, especially young people who like new and modern things.

Often people feel that they can find the latest styles only in the city. Other people are interested in technological (科技的) things and high-tech jobs and think they can find them only in a big city. If they want to find a job, especially a good position in a company, they feel they have to live in a city. To get these jobs, they are willing to put up with many of the disadvantages (不利因素) of city life such as heavy traffic and pollution.

However, it is now possible to enjoy a higher quality of life in the countryside and still enjoy some of the advantages (好处) of living in the city.

Nowadays, travel is fast and information is available (可获得的) on the Internet, so many people are able to do their work in home offices.

Because they have e-mail and personal computers, they don't have to be in big cities to do their business. It is not important where they actually work because the results of their work can be sent everywhere with technology. Now they can enjoy life in the countryside and still be able to do good business and successful careers.

小题1:The underlined phrase “put up with” (in Para. 3) probably means “_____”.

A.change

B.stand

C.be angry with

D.be pleased with小题2:Now people can enjoy life in the countryside and still be able to do good business and successful careers _____.

A.because of the Internet and fast travel

B.because of e-mail and personal computers

C.because travel is fast

D.because the rural areas are developing faster than cities小题3:What is the author's opinion?

A.She / he prefers to live in the countryside rather than live in the city.

B.She / he prefers to live in the city rather than live in the countryside.

C.She / he likes both city life and countryside life.

D.It is not clear which life she / he prefers.小题4:What would be the best title for this passage?

A.Life in the city

B.Life in the country

C.Go and live in the city

D.Go and live in the country

查看答案
微信公众账号搜索答案