实验室用氯化钠固体配制100mL1.0mol•L-1的NaCl溶液,有如下操作步

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问题:

实验室用氯化钠固体配制100mL 1.0mol•L-1的NaCl溶液,有如下操作步骤:

①用托盘天平称量______g NaCl晶体放入小烧杯中,加适量蒸馏水溶解;

②继续向容量瓶中加蒸馏水至液面距刻度线1-2cm处,改用______小心滴加蒸馏水至溶液凹液面的最低处与刻度线相切;

③把①中所得溶液小心地转入______中;

④将容量瓶塞紧,充分摇匀;

⑤用少量蒸馏水洗涤烧杯与玻璃棒2-3次,洗涤液一并转移到容量瓶中.

(1)将上述步骤的空白处填空;

(2)本实验操作步骤的正确顺序是(填序号,不能重复)______;

(3)试分析下列操作对所配得溶液的浓度有何影响(填:“偏高”、“偏低”、或“无影响”)

①容量瓶用蒸馏水洗净后没有干燥就直接用来配溶液,所配得溶液的浓度______;

②定容时,仰视刻度线,所配得溶液的浓度______;

③定容后,加盖倒转摇匀后,发现液面低于刻度线,所配得溶液的浓度______.

考点:配制一定物质的量浓度的溶液
题型:问答题

高渗性缺水患者,其缺水程度为轻度,患者缺水量为体重的()

A.2%~4%

B.3%~5%

C.4%~6%

D.5%~7%

E.6%~8%

题型:问答题

Monkeys prefer heavy metal to classical music, according to researchers at the University of Wisconsin whose findings are published this week in Biology Letters.

Scientists played a selection of music to a group of South American cotton-top monkeys but the only sound that got a reaction were from the heavy metal band Metallica. They were seemingly disinterested in Led Zeppelin, Miles Davis and Bach, but after the beautiful sound of Master of Puppets by Metallica was played the monkeys calmed down.

"Monkeys interpret rising and falling sounds differently than humans. Oddly, their only response to several samples of human music was a calming response to the heavy-metal band Metallica," said Professor Charles Snowdon, from the University of Wisconsin-Madison.

Rather than making them excited or aggressive, the heavy metal tracks had a comforting effect. Dr Snowdon, who teamed up with National Symphony Orchestra musican David Teie, also played the monkeys music composed specifically for them. Although they enjoyed Metallica, they were much more interested in these pieces.

A melody(乐曲) based on the short calls of scared monkeys led to anxiety levels rapidly growing, researchers found, while one based on long calls the creatures make when they are happy had a calming effect.

Frans B.M. de Waal, a professor of psychology at Emory University who studies animals, said the findings appear to say more about how monkeys respond to the sounds they make than they do about music or the evolution of music.

Dr Snowdon no longer has a monkey colony to use in his research, but he said his co-author David Teie is exploring the concept of music for cats.

"If we understand how we can affect their emotional states through using musical sound and aspects of our speech, maybe those of us living with companion animals can have a better relationship with them, too," Snowdon said.

小题1:The research mentioned in the passage is mainly about ______.

A.the change of music over time

B.animals’ response to music

C.special music for animals

D.the origin of music小题2:When the monkeys heard the music they liked, they ______.

A.looked anxious

B.became restless

C.felt at ease

D.made long calls小题3:According to the passage, the monkeys are most interested in the music ______.

A.of Led Zeppelin

B.of Miles Davis

C.of Metallica

D.specially composed for them小题4:The aim of the research, according to Professor Snowdon, is to ______.

A.build better ties between animals and humans

B.compare monkeys and cats in term of music

C.develop new music based on animals’ calls

D.find better ways to keep animals under control

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男性,26岁,发现心尖区Ⅲ级收缩杂音3年,发热10天。可闻收缩中、晚期喀喇音,有杵状指,足底有无痛性小出血点。

对诊断最有意义的心脏超声表现为()

A.瓣膜上出现赘生物

B.主动脉瓣关闭有裂隙

C.二尖瓣口狭窄

D.连枷样瓣叶

E.主动脉瓣增厚

题型:问答题

( )是指以宏观经济形势、行业特征及上市公司的基本财务数据作为投资分析对象与投资决策基础的投资分析流派。

A.基本分析流派

B.技术分析流派

C.行为分析流派

D.学术分析流派

题型:问答题

交付是指经过承运人按照货运单证上的要求,按时、完好地在约定的目的地把承运的货物交给收货人,程序有以下内容()

A、卸货

B、通知

C、交接

D、验收

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