题目内容
【题目】常温下，在0.01 molL1硫酸溶液中，水电离出的氢离子浓度是
A．5×1013 mol L1 B．0.02 mol L1 C．1×107 mol L1 D．1×1012mol L1
【答案】A
【解析】溶液中共有两部分H+：水电离出来的H+和硫酸电离出来的H+。其中硫酸电离出来的H+为c(H+)=0.01×2= 0.02 mol L1。水电离出来的H+要小于107mol L1，硫酸电离出来的H+是主要的，因此认为溶液中的H+的总浓度就是0. 02 mol L1，根据c(OH)= Kw /c(H+)，溶液中的c(OH) =1014/0.02=5 × 10 13 molL1 。因为水电离出来的H+和OH的个数相等(不受任何条件限制)，则水电离出来的H+浓度就是5×1013 mol L1。
鸿图图书寒假作业假期作业吉林大学出版社系列答案【题目】
认真阅读下列短文，并根据所读内容在文章后表格中的空格里填入最恰当的单词。注意：每空格1个单词。
Are you a procrastinator?
Following a schedule and doing things on time is extremely important in today's busy world. Unfortunately, not everyone is good at doing this. Many people are procrastinators; they put off doing things that they need to until it's too late.
We all put off doing things at times. Statistics show that 90% of university students will often put off studying for a test or writing an important paper the night before, 25% of university students put off almost everything all the time. This more serious form of procrastination can result in a student dropping out of school. Students who put off doing their assignments once in a while get further and further behind in their studies. Before long, they feel completely helpless. For the chronic（长期的）procrastinator, often the only way to solve this problem is to quit school.
According to recent studies, there are three main reasons that students put off doing things. First, many have poor time-management skills and often try to do too much in too little time. In the end, these students often feel helpless and will put off doing many things they need to. Another reason why students put off doing things is that they feel a subject is boring and have difficulty concentrating on an assignment.These students will often avoid doing something because they don't like it. A third reason why many students put off doing things is that they often worry that their work will never be as good as it should be and fear failure of any kind, which, unfortunately , can often cause these students to put off doing any work at all.
Do you recognize any of these signs in yourself? If so, you may want to do something about your tendency towards procrastination. The following five tips may be helpful.
First, list the things in life that are important to you, and then list the reasons why you are at school or university. Look at the two lists and see where they match. Is there something you need to do in order to achieve a life goal?
Second, chose realistic goals for yourself; don't try to do more than you can.
Third, once you have identified our goals, list them and ask yourself "Which should I do first?" As you become more aware of what you need to do and when you need to do it, you will feel more in control and will be able to complete tasks on time.
Fourth, manage your time wisely. Create a schedule that allows adequate time for accomplishing a goal; for example, your schedule should give you enough time to study for and pass a test, as well as time to relax.
Finally, when you accomplish a goal, do something good for yourself as a reward.
If you believe that you are a chronic procrastinator, you should try to get help before it is too late. Talk to a professional, and discuss the problem. If you are a mild procrastinator, make sure to keep yourself motivated, but don't worry too much.
Are you a procrastinator? | |
Frequency of procrastination | ·Everyone puts off doing things【1】 . ·90% of university students will often put off dong things. ·25% of university students 【2】 doing things all the time. |
【3】 that procrastination will lead to | ·At the beginning, they get further and further behind in their studies. ·Before long, they feel completely helpless. ·For the chronic procrastinator, often he or she has no 【4】____ but to quit school. |
Main reasons for procrastination | ·First, many are not skillful at managing time well. ·Second, they feel a subject is boring, which makes it difficult for them to 【5】___ on an assignment. ·Third, they expect to do everything【6】 and fear failure of any kind. |
【7】 to avoiding procrastination | ·First, identify your life goals. ·Second, choose realistic goals for yourself ·Third, list your goals in order of priority. ·Fourth, manage your time in a 【8】 way. ·Finally, 【9】 yourself for accomplishing a goal. |
Advice to procastinators | ·For a chronic procrastinator,【10】 a professional. ·For a mild procrastinator, make sure to keep yourself motivated, and don't worry too much. |