问题 选择题

现有CO和CO2混合气体,采用图是实验室装置可以:①检验CO2气体,②分离CO和CO2混合气体,③干燥CO或CO2气体.实验所需的试剂有:稀盐酸、浓硫酸、氢氧化钠溶液和澄清石灰水.下列说法不正确的是(  )

A.甲中应盛放氢氧化钠和石灰水的混合溶液

B.乙中应盛放浓硫酸

C.丙中应盛放稀盐酸

D.首先分离得到的是CO2气体,而后得到CO气体

答案

A、甲中盛放的液体能吸收二氧化碳,一般用氢氧化钠溶液吸收的完全,又因为该实验装置可以检验二氧化碳的存在,所以甲中应盛放氢氧化钠和石灰水的混合溶液,故A说法正确;

B、乙中盛放浓硫酸是为了干燥分离出来的气体,因为浓硫酸具有吸水性,故B说法正确;

C、甲中的氢氧化钠与二氧化碳生成碳酸钠和水,氢氧化钙与二氧化碳反应生成碳酸钙和水,所以丙中盛放盐酸,盐酸与碳酸钠、碳酸钙反应又生成二氧化碳,故C说法正确;

D、由于甲中装有能吸收二氧化碳的溶液,将一氧化碳和二氧化碳的混合物通过时,二氧化碳被吸收,应该先直接分离出一氧化碳,故D说法错误.

故选D.

单项选择题
阅读理解

It’s not always easy to eat healthy foods when others seem to eat whatever they want. Follow the tips and know that it will make a difference in your life.

What about sweet foods?

Everyone likes the taste of sweet foods! Small amounts of sweet foods can be part of a healthy meal plan. Sugary foods include soda, sweetened fruit drinks, honey, and candy. Desserts such as cakes, pies, cookies, and ice cream contain a lot of fat as well as sugar. If you choose to eat any of these sweet foods, just have a small amount at the end of a healthy meal. Have a piece of fruit if you are still hungry. Drink water, sugar-free soda, and sugar-free fruit drinks, if you are thirsty, instead of drinks that are all high in sugars.

How much should you eat?

Your height, weight, age, whether you are a boy or a girl, and how active you are will affect how much food you need to eat each day to stay at a healthy weight. Everyone is different. Talk to your doctor or diet expert about how much to eat, especially if you need to lose weight. If you take in more food than your body burns, you will gain weight. If you take in less food than your body burns, you will lose weight. Being active and eating smaller amounts of food and fewer sweet or fatty foods can help overweight kids lose weight in a healthy way. You will keep your heart healthy, too.

67.Which of the following desserts is NOT mentioned in the passage?

A.Cakes.                     B.Pies.                        C.Cheese.                           D.Cookies.

68.How much we should eat will depend on the following EXCEPT___________.

A.our body size                      

B.the time we spend taking exercise

C.how old we are             

D.the money our family earns

69.According to the passage, which of the following statements is TRUE?

A.The more food our body burns, the faster we will lose weight.

B.The more food we eat, the more food our body will burn.

C.The more active we are, the more food we need to eat.

D.The more food we eat, the more weight we will gain

70.The author advises overweight children to_________.

A.eat healthy foods and take regular exercise

B.pay much attention to their heart health

C.keep foods containing sugar and fat away

D.talk to their doctor and join a health club