问题 问答题

(1)在标准状况下,44.8L的NH3气体质量为______g.其中含______mol氮原子,含______个氢原子.

(2)质量相等的HCl、CO2、NH3、CH4四种气体中,含有分子数目最少的是______,在相同温度和相同压强条件下,体积最大的是______,密度最小的是______.

答案

(1)n(NH3)=

44.8L
22.4L/mol
=2mol,其质量为2mol×17g/mol=34g,n(N)=2mol,n(H)=6mol,氢原子个数为6NA个,

故答案为:34;2;6NA

(2)由m=nM,N=nNA,等质量时,摩尔质量越大的分子数最少;相同温度和相同压强条件下,Vm相同,摩尔质量最小,其物质的量最大,则体积最大;由ρ=

M
Vm
可知,M越小,其密度越小;

摩尔质量由大到小为CO2>HCl>NH3>CH4

所以等质量时分子数最少的为CO2,在相同温度和相同压强条件下,体积最大的是CH4,密度最小的是CH4

故答案为:CO2;CH4;CH4

阅读理解

Ask someone what they have done to help the environment recently and they will almost mention recycling, which is the process (过程) of treating used things, such as paper or steel so that they can be used again. Recycling in the home is very important of course. However, being forced to recycle often means we already have more things than we need. We are now dealing with the results of that over-consumption in the possible greenest way, but it would be far better if we did not bring so many things home in the first place.

Here is an example. In the UK, the total of packaging increased by 12% between 1999 and 2005. It now makes up a third of a household’s waste. In many supermarkets, foods are packaged twice with plastic and cardboard.

Too much packaging causes serious environmental problems. The UK is running out of different kinds of ways for dealing with this unnecessary waste. If such packaging is burnt, it gives off greenhouse gases which go on to cause the greenhouse effect (效果). Recycling helps, but the process itself uses energy. The best way of avoiding this problem is to stop producing such unnecessary things in the first place. Food waste is another serious problem, too. Too many supermarkets encourage customers (消费者) to buy more than they need. They seldom encourage customers to reuse their plastic bags, for example. However, a few of them are coming round to the idea that this cannot continue.

But this is not just about supermarkets. It is about all of us. We have learned to connect packaging with quality (质量). We have learned to think that something unpackaged is of poor quality. Is it true for all the products? In fact, more and more companies realized the importance of protecting the environment. They try to package what really should be packaged, including products in good quality.

As more of us recycle, we are beginning to realize how many unnecessary things are being collected. We need to face the waste of our daily life. Although many people have taken action to recycle, we have a high mountain to climb.

小题1:What does the underlined word “over-consumption” mean?

A.Making the environment green.

B.Recycling as much as possible.

C.Making more products than necessary.

D.Having more things than being needed.小题2:What is the main purpose of the second paragraph?

A.To show the facts of over-used packaging.

B.To talk about the possible greenest ways.

C.To teach people how to do recycling at home.

D.To express worries about environmental problems.小题3:What can be inferred from the fourth paragraph?

A.Unpackaged products are of bad quality.

B.Other products are better packaged than food.

C.We can’t always connect quality with packaging.

D.Supermarkets should care more about packaging.小题4:What does the passage mainly talk about?

A.Supermarkets should recycle first.

B.Packaging causes serious problems.

C.Needless things are mostly recycled.

D.Recycling should be done in the first place.

单项选择题