要配制1 mol·L-1的NaOH溶液100mL,下面操作正确的是() A.称取

题型:选择题

问题:

要配制1 mol·L-1的NaOH溶液100mL,下面操作正确的是(   )

A.称取8g NaOH固体,放入烧杯里,用量筒量取100mL 蒸馏水倒入烧杯中,搅拌充分溶解

B.称取8g NaOH固体,放入100mL量筒中,加水,充分溶解并稀释至100mL

C.称取8g NaOH固体,放入100mL容量瓶中,加蒸馏水溶解,再加水至刻度线,盖好瓶塞,反复摇匀。

D.称取8g NaOH固体,放入烧杯里,加适量水溶解,将溶液转移到容量瓶中,洗涤烧杯和玻璃棒,把洗液一并转移到容量瓶中,再加水将溶液体积调至100mL

考点:物质的量
题型:选择题

如图,要在河流的南边,公路的左侧M区处建一个工厂,位置选在到河流和公路的距离相等,并且到河流与公路交叉A处的距离为1cm(指图上距离),则图中工厂的位置应在______,理由是______.

题型:选择题

3岁,男,1年内反复肺炎3次,有反复鼻塞、流涕和(或)咳嗽、咳痰病史。

如要明确该患儿是否有中性粒细胞缺陷,需进行的免疫学检查为()

A.T细胞分类

B.淋巴细胞转化实验

C.免疫球蛋白

D.NBT

E.HLA

题型:选择题

I was a single parent of four small children, working at a low paid job. Money was always tight, but we had a (1) over our heads, food on the table, clothes on our backs, and if not a lot, always (2) . Not knowing we were poor, my kids just thought I was (3) . I’ve always been glad about that.

It was Christmas time, and although there wasn’t (4) for a lot of gifts, we planned to celebrate with a family party. But the big (5) for the kids was the fun of Christmas (6) .

They planned weeks ahead of time, asking (7) what they wanted for Christmas. Fortunately, I had saved MYM120 for (8) to share by all five of us.

The big (9) arrived. I gave each kid a twenty-dollar bill and (10) them to look for gifts of about four dollars each. Then everyone scattered. We had two hours to shop; then we would (11) back at the "Santa’s Workshop"

Driving home, everyone was in high Christmas spirits, (12) my younger daughter, Ginger, who was unusually (13) She had only one small, flat bag with a few candies—fiftycent candies I was so angry, but I didn’t say anything (14) we got home. I called her into my bedroom and closed the door, (15) to be angry again. This is what she told me.

"I was looking (16) thinking of what to buy, and I (17) to read the little cards on the ’Giving Trees’. One was for a little girl, four years old, and all she (18) for Christmas was a doll. So I took the card off the tree and (19) the doll for her. We have so much and she doesn’t have anything. "

I never felt so (20) as I did that day.

4().

A.angry 

B.rich 

C.patient 

D.bitter

题型:选择题

实现从主机名到IP地址映射服务的协议是______。

A.ARP

B.DNS

C.RIP

D.SMTP

题型:选择题

在法兰连接中,法兰与管内介质不接触的连接方式为( )。

A.平焊法兰

B.对焊法兰

C.高颈法兰

D.高压螺纹法兰

更多题库