问题 填空题

请用化学知识解释下列问题:

(1)妈妈在厨房里炒菜,我在窗外就闻到了香味.______.

(2)从细口瓶倒液体标签要朝着手心的原因是______.

(3)蛋黄派充氮气包装,其原因是______.

(4)白炽灯泡钨丝上放少量红磷,其原因是______.

答案

(1)炒菜时闻到香味是因为分子的不断运动,香味分子运动到空气中,进入人们的鼻孔.

(2)从细口瓶倒液体标签要朝着手心的原因是防止药液流出腐蚀标签.

(3)氮气化学性质不活泼,可做保护气,蛋黄派充氮气包装,是为了延长食品的保质期.

(4)白炽灯泡钨丝上放少量红磷,其原因是除去灯泡内少量的氧气,防止钨丝被氧化.

故答案为:(1)分子在不断运动.

(2)防止腐蚀标签.

(3)氮气化学性质不活泼.

(4)除去灯泡内少量的氧气.

阅读理解
阅读下面发表在博客中的短文,根据短文内容,在短文后1-5小题给出的横线上填入恰当的词语。
                       Problems
A B C
     My problem is my parents.
They never stop going on about
how I should keep my room tidy,
keep my hair tidy and wear smart
clothes. They even make me do
the washing-up after dinner every
night! None of my friends have got
such terrible parents. What should
I do?
Helen

     My best friend has suddenly
turned her back on me and I don't
know why! Last week we phoned
each other every day and e-mailed
too, and over the weekend we went
shopping together and she was fine.
But at school on Monday morning
she didn't look at me or speak to
me. I don't know what I've done.
She now spends all her time with
another group of friends.
Jane
I have a really bad habit of
chewing (嚼) the ends of
my hair. I try to stop, but I
can't! My mom is starting to
get really angry about it. Have
you got any ideas?
Gina




                       Advice
① Hi _________, Why should
your parents do all the washing-up?
You should help around the house-it's
only fair. I don't think you should
change your looks though. Young
people should look like young people.

②Hi_________, Wearing your hair
pulled back in a ponytail (马尾辫) will
help keep it out of your mouth. When
you feel like chewing something, try
bubble gum (泡泡糖). Give yourself
time and you should be able to break
this habit. The first few days are usually
the hardest. Good luck!
③Hi ________, Don't worry
about it so much! Phone your
friend up as usual and she
won't be able to refuse you.
I am sure you will get along
well with each other.
Everything will be fine.
1. 根据所读内容将Helen, Jane, Gina 三个名字分别填入相应的横线上。
①________________________
②________________________
③________________________
2. The three girls wrote to ask for ________________________.
3. The underlined words "turned her back on me" means "_______________________" in Chinese.
4. It is clear that Helen is not ________________________ with her parents.
5. According to the advice, Jane should ________________________ her friend as usual.
单项选择题