下列对露置在空气中已部分变质的氢氧化钠溶液样品进行的相关实验_爱下问搜题

搜题请搜索小程序“爱下问搜题”

问题不定项选择题

下列对露置在空气中已部分变质的氢氧化钠溶液样品进行的相关实验中，实验现象及结论合理的是[ ]

A．取少量溶液样品，滴入氯化钡溶液，有白色沉淀生成

B．取一定量溶液样品，滴入稀盐酸，立即有大量气体产生

C．取一定量溶液样品，滴入适量的澄清石灰水，过滤，向滤液中滴加酚酞溶液，溶液变红，证明原样品中含有氢氧化钠

D．向溶液样品中加入适量的澄清石灰水至恰好完全反应，过滤，可除去样品中的杂质

答案

AD

完形填空

“Ring… ring…” the telephone suddenly rang. Sam got up to the call. It was his aunt. “Sam, are you still at home?” she asked in surprise. Sam 1ooked at the clock. It was already 7:30 a. m. “Oh, my goodness! There’s an important today,” Sam shouted out. He hurried to wash his face and get .When he was going to leave the house, he remembered that he had not put away his books. He ran quickly to the door and put them into the bag. He then went to the bus stop to go to school as as she could. When he got into the classroom, his classmates were writing. “Why are you so ?” asked the teacher. ‘‘I’m sorry, sir,” Sam answered, afraid of looking down. “It was my clock. It failed to wake me up this morning and....” “Don't say anything about it,” his teacher him. “Don’t try to come late next time!” Sam said yes and walked to his quickly. But when he tried to do the paper, he could not think in a right way. He put his head on the desk and said, “What a day it has been for me!”

解答题

某公司在地方电视台插播一条30秒广告，宣传自已的产品，每天播出一次，连播两周共付人民币35.7万元，平均每秒多少元？