过氧乙酸（CH3COOOH）是一种常用消毒剂，目前广泛用于环境消毒．_爱下问搜题

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问题填空题

过氧乙酸（CH₃COOOH）是一种常用消毒剂，目前广泛用于环境消毒．过氧乙酸由______种元素组成，其中C、H、O元素的原子个数比为______；若对1m³空间进行有效消毒需要0.2%的过氧乙酸3g，现对80m³的空间进行有效消毒，需要0.2%的过氧乙酸______g．

答案

根据过氧乙酸的化学式CH₃COOOH，可知过氧乙酸由碳、氢、氧三种元素组成；根据过氧乙酸的化学式CH₃COOOH，标在元素符号右下角的数字表示一个分子中所含原子的个数，可得过氧乙酸中碳、氢、氧的原子个数比为2：4：3；

由题意可知，1m³空间进行有效消毒需要0.2%的过氧乙酸3g，则对80m³的空间进行有效消毒，需要0.2%的过氧乙酸的质量是：3g×80═240g．

故答为：三，2：4：3，240g．

阅读理解

阅读理解。

                                                                1
Dear guest,
     We want to do our best to help with the environmental protection, but we do provide
washing things (toothbrush, toothpaste, bath shampoo, etc.)
     If you forget to bring any of these with you, just dial 9 and call the guestroom
department. If you wish, we shall send you what you need for free.

                                                               2
Dear guest,
     The hotel wishes to save the world's natural resources (资源). Every day, tons of
detergent (洗涤剂) and millions of tons of water are used to wash towels (毛巾) which
have been used only once.
     Here's how you can help:
    ﹡A towel on the rack (架子)means: "I'll use it again."
    ﹡A towel on the floor means:"Please change."

                                                               3
Dear guest,
    Your bedclothes are changed every day.
   If you'd like to help save the world's resources, just leave this card in the morning.
Your bed will be made up as usual but the sheets will not be changed. In this way, we
can both help protect our environment.

1. The three cards can most likely be found in a .

A. hotel
B. supermarket
C. bookshop
D. bank

2. A guest who forgets to bring a toothbrush with him .

A. must buy one from the hotel
B. should get one ready by himself
C. can get one from the hotel for free
D. may ask someone to buy one for him

3. If guests want to get their towels changed, they should leave them .

A. in the rack
B. on the floor
C. under the bed
D. in the desk

4. The third card tells guests .

A. how to get the towel changed
B. where to get the towels changed
C. where to get the bedclothes changed
D. how to get the bedclothes changed

5.The aim of the article is to .

A. follow the rules of the hotel
B. get a good service
C. protect our environment
D. All of above

填空题

某容器质量为200g，装满水后总质量是700g，装满某液体时总质量是600g，则该容器的容积为______cm³，此液体的密度为______kg/m³．