问题 选择题

在化学反应:4HgS + 4CaO =" 4Hg" + 3CaS + X中,X的化学式为

A.SO2

B.SO3

C.CaSO3

D.CaSO4

答案

答案:D

题目分析:由反应的化学方程式4HgS + 4CaO =" 4Hg" + 3CaS + X可知,

反应前    反应后

Hg原子       4          4

S原子        4          3

Ca原子       4          3

O原子       4          0

根据质量守恒定律,化学变化前后原子的种类、数目不变,可判断生成物X分子中含有1个S原子、1个Ca原子和4个O原子,则物质X的化学式为CaSO4。故选D

点评:本题考查化学式的推断,利用质量守恒定律中的原子守恒来推断是常用的方法,学生应注意守恒思想在解题中的重要作用。

综合
阅读理解

根据短文内容,从下面A—F选项中选出能概括每一段主题的最佳选。选项中有一项为多余选项。)此题答案写在二卷

A.Start early

B.Set up a side business

C.Build your network

D.Predict what will happen in the futureE. Expand your knowledge

F. Be willing to spend your time and money

61._______

Who doesn’t want to have a good future? It’s something everyone desires. The one who determines whether or not you have a good future is you. Don’t wait until something bad happens. Don’t wait until you lose your job. It is you who must take action. Start now while the situation is still good. Why? Because it takes time to build something. Let’s say you want to build an alternative income stream that you can rely on. You can’t build that overnight. Doing that takes time and persistence. If you don’t start early, it might not have been ready by the time you need it.

62. _______

It could be difficult to spend your time and money on something that doesn’t give you immediate return. But it’s important that you do that and it is one of the best ways to prepare yourself for the future. Those who are wise always spare some time and money in advance to invest in their future. If you don’t, your progress will be slow and you wouldn’t be ready in time.

63._________

I’m sure you’ve heard the advice “ Don’t put all your eggs in one basket.” It’s good advice, but how can you apply if you know only one basket? By expanding your knowledge, you will know what possibilities there are so that you can find new opportunities. Expanding your knowledge can also help you see something you already know in a different light. You can see it from a new perspective. Overall, expanding your knowledge improves your ability to make good decisions.

64. _______

Building a side business is one of the best ways to invest in your future. In fact, it’s a favorite of mine. Not only can it help you prepare for unexpected job loss and provide you with an alternative income source, but also it teaches you a lot in the process. You will learn much because you deal with the real world.

65. ________

Your network of friends and acquaintances is one of the best assets (资产) you could have. It can inform you of new opportunities. It can also help you find the resources you need. By building your network, you are preparing for a time in the future when you might need help from it. But build your network with right motivation. Don’t build it with the motivation to get something from it.