题干

下列有关实验的操作正确的是(   )

A:容量瓶、量筒和滴定管上都标有使用温度,量筒、容量瓶无“0”刻度,滴定管有“0”刻度;使用时滴定管水洗后还需润洗,但容量瓶水洗后不用润洗

B:检验某溶液是否含有SO42时,应取少量该溶液,依次加入BaCl2溶液和稀盐酸

C:为观察Mg条在CO2气体中的燃烧,在一个底部铺有少量玻璃棉的集气瓶中收集满  CO2气体,取一小段除去表面氧化膜的Mg条用坩埚钳夹持点燃后迅速投入上述集气瓶底部

D:用干燥且洁净的玻璃棒蘸取NaClO溶液,滴到放在表面皿上的pH试纸上测pH值

上一题 下一题 0.0难度 选择题 更新时间:2019-11-03 11:43:36

答案(点此获取答案解析)

A

同类题3

根据短文内容,用正确的信息填空,完成下面的表格,每空一词。

    Service on the 102-km high-speed railway between Shenzhen and Guangzhou started on December 26, 2011. A non-stop trip between the Guangzhou South Station and the Shenzhen North Station takes 35 minutes at full speed.

    The train runs at the highest speed of 300 km per hour. All 36 pairs of trains run every day. A one-way first-class ticket costs 100 yuan. A second-class one costs 75 yuan, 5 yuan cheaper than a second-class ticket on the slower line.

    A high-speed train has 556 seats, including 16 seats in the VIP rooms and 50 in the first-class carriage (车厢). It offers more advanced facilities (先进的设施). For example, the seats are more comfortable, there are toilets for the disabled (残疾人), and there are power outlets (电源插座) in the first-class carriage.

    The high-speed service between Guangzhou and Shenzhen will be a convenient choice for many people. “I won't need to travel to the Guangzhou East Station to take a train to Shenzhen,” said Wang Yi, who lives in Panyu district in Guangzhou.

    Many people still prefer the slower trains, because the terminals (终点站) of the high-speed trains are far away from the centres of both cities. “I would not like to take a high-speed train to Shenzhen. I live in the centre of Guangzhou. First I have to get to the Guangzhou South Station. It is a waste of time for me,” said Zhang Lu.

High⁃speed railway between Shenzhen and Guangzhou

On December 26, 2011, the high-speed railway between Shenzhen and Guangzhou started to be in service. It only takes ____minutes to get to Shenzhen from Guangzhou.

Speed

The train runs at the ____speed of 300 km per hour.

Ticket price

●A____first-class ticket costs 100 yuan.

●A one-way second-class one costs 75 yuan, 5 yuan ____than a second-class ticket on the slower train.

Service

●All 36 pairs of trains run between Shenzhen and Guangzhou ____.

●A high-speed train has 556 seats, including 16 seats in the VIP rooms and 50 in the ____carriage.

●It ____more advanced facilities for passengers. The seats in the first-class carriage are more ____, and there are toilets for the disabled and power outlets.

Opinions

●Wang Yi said he could take the high-speed train to Shenzhen from Panyu easily.

●Zhang Lu said it was a waste of____for him to take the high-speed train to Shenzhen because the Guangzhou South Station is far away from the ____of Guangzhou.