现用质量分数为36.5%、密度为1.20g·cm-3的浓盐酸来配制100mL1._爱下问搜题

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问题实验题

现用质量分数为36.5%、密度为1.20 g·cm^-3的浓盐酸来配制100 mL 1.5 mol/L的稀盐酸。可供选择的仪器有：①玻璃棒 ②烧瓶 ③烧杯 ④胶头滴管 ⑤量筒⑥容量瓶 ⑦托盘天平 ⑧药匙。

请回答下列问题：

（1）上述仪器中，在配制稀盐酸时用不到的有__________(填代号)。

（2）经计算，需浓盐酸的体积为________ 。现有①10 mL ②20 mL ③50 mL ④100 mL四种规格的量筒，取用浓盐酸应选用的量筒是________(填代号)。

（3）在配制过程中，其他操作都准确，下列操作中：错误的是________，能引起误差偏高的有_________（填序号）。

①洗涤量取浓盐酸后的量筒，并将洗涤液转移到容量瓶中

②稀释后的盐酸在空气中放置过久

③定容时，加蒸馏水超过标线，又用胶头滴管吸出

④转移前，容量瓶中含有少量蒸馏水

⑤定容摇匀后，发现液面低于标线，又用胶头滴管加蒸馏水至标线

⑥定容时，俯视标线

答案

（1）②⑦⑧

（2）12.5mL；②

（3）①②③⑤⑥；①⑥

解答题

甲乙两地相距390千米，一辆汽车上午10时从甲地开出，下午4时到达乙地，这辆汽车每小时行驶多少千米？

完形填空

阅读下面短文，从短文后各题所给的四个选项（A、B、C和D）中，选出可以填入空白处的最佳选项，并在答题卡上将该项涂黑
Half a year before graduation from college, my son began to seek a job.  the financial crisis, fewer companies would like to    new staff. My son targeted a company that was  to employ only one person   there were more than 20 people filing their resumes.
After the interview, there would only be 3 who could enter the final round, which would later   one person to be employed. Everything seemed to go quite    and my son passed the first round and entered the final round in a week.
On the day of the final interview, my son and other two    arrived at the interview place on time,   the test. The interview was unbelievably . The interviewer only said to them, “All of you are very super. Please go home and wait for our   . We will tell you the    in 3 days. Good luck to all of you！” On the morning of the third day, my son received a text from the company shortly after breakfast that he was not employed. We all felt very   .
In nightfall that day, my son suddenly told me    on phone, “Dad, I have been employed!” Greatly surprised, I could not wait to ask him, “ What’s the whole   ?” My son told me that he received another text saying that he was employed. Actually the first text sent to my son was also    of the test in the interview. Three men received the same text this morning and only my son ’s    was “ Thank you” while the others said “Goodbye”.
Only then did I know that my son ’s hope    in that way. That is, when you feel disappointed, do not    to say “Thank you ” to the one who disappoints you. Saying “Thank you” shows respect for others’ work and shows your grand   . Therefore, while under the same condition, you will get the upper hand in terms of    compared with others!

D．Contrary to

A．watching over

B．waiting for

C．thinking about

D．looking into

A．information

D．disappointed

D．personality

B．opportunities