问题 问答题

维生素C主要存在于蔬莱和水果中,它能促进人体生长发育,增强对疾病的抵抗力.目前药店里有一种“维C泡腾片”的药品能补充人体对维生素C的需求.一次小明看到爷爷冲饮这种药品的过程:在一杯温开水中放人一片该药品,药品迅速溶解,同时出现了大量的气泡.小明对这一现象产生了浓厚的兴趣,于是他向爷爷要了几片这种“维C泡腾片”在家中进行实脸;在盛有温水的杯中加入该药品,并用燃着的火柴伸到杯口,发现火柴熄灭,由此小明初步推测了该气体中含有的成分,但还不能最终确定.

为了进一步确定自己的推测.第二天小明拿着药品去学校实验室做了如下实验:

操作感觉气体的色、味气体通入紫色石蕊试液气体通入澄清石灰水
现象无色、无味紫色石蕊试液变红色澄清石灰水变浑浊
(1)分析小明的实验现象,可以确定该气体中一定有______,写出这种气体与澄清石灰水发生反应的化学方程式:______.

(2)从该“维C泡腾片”说明书的注意事项中,小明还发现了这样的叙述:冲饮时水温不能高于80℃;冲后即服用.从中你可推侧维生素C还有哪些性质?______.(写出一项即可)

答案

(1)二氧化碳不燃烧不支持燃烧,能使带火星木条熄灭,将二氧化碳通入紫色石蕊试液中,二氧化碳与水反应生成碳酸,碳酸使紫色石蕊试液变红;二氧化碳能与氢氧化钙反应生成碳酸钙沉淀和水,结合题中给出的实验现象,确定该气体为二氧化碳,与石灰水反应的方程式为:CO2+Ca(OH)2=CaCO3+H2

(2)根据“维C泡腾片”说明书的注意事项“冲饮时水温不能高于80℃;冲后即服用”说明维生素C受热易分解.

故答案为:CO2        CO2+Ca(OH)2=CaCO3↓+H2O     受热易分解

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根据短文内容,从短文后的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。

     Are you truly happy? Do you even know what it means to be happy and what it takes to achieve happiness?

51.____ The following are a few tips that I follow to create happiness in my life.

     Make a plan for attaining goals that you believe will make you happy. Your moods will very likely increase

if you are going after something you value.

     Surround yourself with happy people. It is easy to begin to think negatively when you are surrounded by

people who think that way. 2.____

     When something goes wrong, try to figure out a solution instead of being absorbed in self pity. Truly happy

people don't allow setbacks to affect their mood because they know that with a little thought they can turn the

circumstances back to their favor. 

     3.____ These few minutes will give you the opportunity to focus on the positive things in your life and will

lead you to continuous happiness.

     4.____ Whether you treat yourself to lunch, take a long, relaxing bath or simply spend a few extra minutes

on your appearance, you will be subconsciously (下意识地) putting yourself in a better mood.

     Finding the humor in situations can also lead to happiness. Find a way to make light of a situation that would

otherwise make you happy.

     Keeping healthy is another way to achieve happiness. 5.____

A. What makes one person happy may be very different from what makes someone else happy.

B. On the contrary, if you are around people who are happy, their emotional state will be infectious.

C. Being overweight or not eating nutritious foods can have a negative effect on your mood.

D. These are important questions for anyone who is seeking happiness to ask themselves.

E. Spend a few minutes each day thinking about the things that make you happy.

F. There are some tips in life that lead to happiness.

G. It's also important to take some time each day to do something nice for yourself.