用18 mol/L的硫酸溶液配制500 mL1 mol/L的硫酸溶液,有下列操作

题型:实验题

问题:

用18 mol/L的硫酸溶液配制500 mL1 mol/L的硫酸溶液,有下列操作步骤:

(1)将溶解后的硫酸溶液立即沿玻璃棒转入容量瓶中;

(2)将量得的浓硫酸倒入烧杯中,加水溶解,然后用蒸馏水洗涤量筒2~3次,倒入烧杯中;

(3)盖上瓶塞,轻轻摇匀即配制完毕;

(4)洗涤烧杯和玻璃棒2~3次,将洗涤液全部转入容量瓶中,加水至离刻度1~2 cm处,改用胶头滴管加水至刻度线;

(5)用量筒量取27. 78 mL的浓硫酸。

先将以上步骤按实际操作的先后顺序排列,_________指出操作中所有的错误和不妥之处____________。

考点:配制一定物质的量浓度的溶液
题型:实验题

单词拼写

1. The room was filled with smoke and it was becoming difficult to b__________.

2. His father's death came as a complete s__________ to all of us.

3. I'm sorry you have m__________ such a wonderful film.

4. The boy __________(绊倒) over a cable and broke his foot.

5. You must be very __________(健康) if you do so much running.

题型:实验题

在除法算式中被除数和除数都扩大4倍,商也扩大4倍.______.

题型:实验题

Don’t have time to read anymore Now you can get free, quick literature via email. More than 100,000 people open their email each day to read a chapter of a book, through Chapter-A-Day, an online book club created two years ago. It’s a free email service that provides a short daily reading for busy people, exposing them to literature they may not find on their own, inspiring some to recommit to the reading habit. About 550 public library systems representing over 3,000 branch libraries already have signed up to offer Chapter-A-Day. Via email, participants get about five minutes’ worth of reading every day. After three chapters are emailed, the installments stop, and those who want to keep reading can borrow the book at their public library or purchase it online. Chapter-A-Day has eight free book clubs, and sells thousands of books each month.

Chapter-A-Day started in 1999 when Suzanne Beecher, a lifelong book lover, realized how many of the women who worked part-time for her software development company didn’t have time in their busy lives to read. She decided to type part of a chapter of a book, and send it to her employees through email. The next day she typed a little more, and continued to send literary installments each day. She says she started getting feedback from the staff about how reading made them feel. "They were interested, and realized that, though they didn’t have time in their busy lives for reading, just reading that little bit each day got them back in the habit." Realizing that many other people could benefit, she decided to take the idea even further and start an email "chapter-a-day" book club to help others ease their way back into daily reading. "Reading makes changes in people’s lives," Beecher says.

Pat Dempsey, a librarian at a public library in Ohio, has found Chapter-A-Day helps her library clients get back in the habit of reading. "It’s a different way to get people hooked on hooks," she says.

The word "installment" in the passage probably means" () ".

A. a library email

B. a rare piece of literature

C. a free novel

D. a part of a book

题型:实验题

电信业务分类为基础电信业务和()。

A、第一类基础电信业务

B、增值电信业务

C、第二类基础电信业务

D、蜂窝移动通信业务

题型:实验题

社会监督是一种非国家性质的监督,人民政协的监督属于国家性质的监督。( )

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