问题 填空题

根据下列各题所给出的数据,可分别求出其“溶质的质量分数”或“溶质的物质的量

浓度”,试判断并求解。

(1)设NA表示阿伏加德罗常数的数值,若某氢氧化钠溶液V L中含有N个OH,则可求出此溶液中______________________为__________________。

(2)已知某氢氧化钠溶液中Na与H2O的个数之比为1∶a,则可求出此溶液中________为________。

(3)已知标准状况下1体积水能溶解500体积的氯化氢,则可求出标准状况下氯化氢饱和溶液中__________为________。

(4)已知将100 mL氯化铝的水溶液加热蒸干灼烧,可得到白色固体b g,则可求出原氯化铝溶液中________为________。

答案

(1)溶质的物质的量浓度mol/L

(2)溶质的质量分数

(3)溶质的质量分数 44.9%

(4)溶质的物质的量浓度mol/L

(1)n=

(2)1∶a⇒m(NaOH)∶m(H2O)⇒w=m(NaOH)∶[m(NaOH)+m(H2O)]。

(3)V(HCl)⇒m(HCl)⇒w=m(HCl)∶[m(HCl)+m(H2O)]。

(4)b g Al2O3⇒n(AlCl3)⇒c。

完形填空

[1]While the Amazon may seem far away, we are all closely connected to it through our actions. Now there are largely the results of great demand for forest products and agriculture land, which makes its plant and animal species in danger. Fortunately, we can help save the Amazon rainforest by making the right choices in our daily lives. By being smart consumers, we can make a difference and help reduce human pressures on the forests and rivers.

[2]Look for forest products that you don’t need to destroy forests to get. We can choose many rainforest products like Brazil nuts and coffee, which can be got without destroying forests. And at the same time the money you provide can help local people to _______________.

[3]Recycle everything possible. Such items as batteries, cloth, glass, paper in our daily life can be recycled with different techniques. For example, the collected glass pieces are taken to a glass recycling factory where they are made into new glass bottles through a series of processing.

[4]Buy the right pets. Many wild animals are illegally caught in the Amazon and sold as pets and large numbers of these animals die in the process. It’s important to ask where the animal comes from and to require a store to give you proof when you decide to buy a pet.

[5]Carefully select the appliances(家用电器) in your home. For example, order low-flow shower heads (喷头), which can reduce your use of hot water and use of energy to heat the water. So it’s wise to select the appliances which can save energy.

[6]Turn off appliances that you are not using and take the plug off them. Switch off TVs, computers, lights, etc. even when they are not being used and make sure the plug off the switch of some appliances that use electricity including TVs, video and audio systems, computers.

小题1:What is the main idea of the text ? (no more than 8 words)

_______________________________________________________________________________

小题2:Fill in the blank in Paragraph 2 with proper words. (no more than 4 words)

And at the same time the money you provide can help local people to ________________________

小题3:List two threats to the wildlife in Amazon.(no more than 5 words)

_______________________________________________________________________________

小题4:What’s the purpose of choosing the appliances carefully ?(no more than 4 words)

_______________________________________________________________________________

小题5:What does the word “they” (Line 2, Paragraph 6) probably refer to?(no more than 1 word)

_______________________________________________________________________________

判断题