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完成下列各题：（1)如何鉴别纯碱、烧碱和小苏打？（2)有四种白色粉末，分别是CaCO3，Ca（OH)2，CaCl2和CaSO4，试

完成下列各题：

(1)如何鉴别纯碱、烧碱和小苏打？

(2)有四种白色粉末，分别是CaCO₃，Ca(OH)₂，CaCl₂和CaSO₄，试用化学方法鉴别。

(3)如何鉴别稀的Br₂水和I₂水(均为橙黄色)。

(4)如何鉴别三种白色固体NaCl，NaBr，NaI？

提问人：网友anonymity 发布时间：2022-01-06

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第1题

The sea is very big. Look at a map of the world. There is less land than sea. The sea covers three quarters of the world.

The sea is very deep in some places. There is one spot, near Japan, where the sea is nearly 11 kilometres deep. The highest mountain in the world is about 9 kilometres high. If that mountain were put into the sea at that place, there would be 2 kilometres of water above it.

If you have swum in the sea,you know that it is salty. You can taste the salt. Rivers,which flow into the sea, carry salt from the land into the sea. Some parts of the sea are less salty than other parts. There is one sea, called the Dead Sea, which is very salty. Because it is very salty, swimmers cannot sink! Fish cannot live in the Dead Sea.

In most parts of the sea, there are plenty of fishes and plants. Some live near the top of the sea.Others live deep down. There are also millions of tiny living things that float in the sea. These floating things are very small. It is hard to see them. Many fish live by eating them.

The sea can be very cold. Divers, who dive deep down in the sea, know this. On the top thewater may be warm. When the diver goes downwards, the sea becomes colder and colder.

Another thing happens. When the diver goes deeper, the water above presses down on him. It’ squeezes him. Then the diver has to wear clothes made of metal. One spot of the sea near Japan is____.

A.nearly nine kilometres deep

B.almost eleven kilometres high

C.two kilometres above the highest mountain in the world

D.two kilometres deeper than the height of the world, s highest mountain

Which of the following is NOT true？A.Fish cannot live in the salty sea

B.The sea gets its salt from rivers

C.Different parts of the sea have different amount of salt

D.There is no fish in the Dead Sea

Fish in the sea live____.A.near the top of the sea

B.deep down in the sea

C.at different depth of the sea

D.on tiny living things in the sea

The deeper divers goes down in the sea,____.A.the warmer the sea becomes

B.the colder they find the sea is

C.the less the water above presses down

D.the heavier their clothes must be

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第2题

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A、We are writing to you to make our packaging requirements as follows.

B、We hope you will find our packaging requirements acceptable and are looking forward to your confirmation.

C、We hope you can understand our status and await for your decision.

D、It’s our usual practice to use cardboard cartons instead of wooden cases, as packaging in cardboard cartons has the following advantages.

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第3题

【单选题】数据导出要用下列哪个命令？

A、mongoexport

B、mongoimport

C、mongorestore

D、mongodump

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第4题

The difficulties of writing largely lie in its ______, demanding the language knowledge of spelling, punctuation, grammar, sentence structure, cohesive devices, and logic in thinking.

A、nature

B、form

C、meaning

D、vocabulary

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第5题

Georgette is currently 30 years old, plans to retire at age 65 and to live to age 85. Her labor income is $25,000 per year, and she intends to maintain a constant level of real consumption spending over the next 55 years. Assume no taxes, no growth in real salary, and a real interest rate of 3% per year. What is the value of Georgette’s human capital? And what is her permanent income?

A、$547,180.50; $20,063.19

B、$537,180.50; $20,063.19

C、$537,180.50; $20,763.19

D、$537,190.50; $20,163.19

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第6题

Besides, in the western Catholic tradition, white represents happiness.

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第7题

The non-Western cultures were undermined in history by_____.

A、fooling people with mass advertisement

B、colonizing the land with military invasion