Yahoo 知識+ 將於 2021 年 5 月 4 日 (美國東岸時間) 停止服務。從 2021 年 4 月 20 日 (美國東岸時間) 起,Yahoo 知識+ 網站將轉為僅限瀏覽模式。其他 Yahoo 資產或服務,或你的 Yahoo 帳戶將不會有任何變更。你可以在此服務中心網頁進一步了解 Yahoo 知識+ 停止服務的事宜,以及了解如何下載你的資料。

2 發問於 科學及數學化學 · 1 十年前

中4 chem功課 - addition polymer

我有問題唔識, 麻煩高手解答!!!

1. A new polymer can be obtained by ethene and propene

(a) would you expect this polymer to be thermoplastic or thermosetting, explain

(b)products made from this new polymer can be recycled. suggest on way of doing this.

2. Used PVC bags are usually destroyed by buring in incinerators. However, this would cause serious polltion. How would the release of these pollutants be minimsed? Explain.

3.why petroleum cannot be replaced?

4. plastics can be recycled, suggest 2 reasons

5. suggest one reason why the disposal of polypropene wastes can cause pollution problems.

6. incineration of PVC produce HCl

(a) state one harmful effect of HCl into atmosphere

(b) How HCl can be removed from incinerator flue gas prior to its discharge to the atmosphere

(c) Suppose that all the chlorine in PVC is converted to HCl upon incineration. Calculate the mass of HCl produced, when a plastic wastes containing 1000kg of PVC is incinerated

7. why polystyrene does not have a constant relative molecular mass?

好多好多唔識, 麻煩哂, point form/key point就ok

萬分感激!!!

更新:

唔該教教我啦

1 個解答

評分
  • 1 十年前
    最愛解答

    功課自己做, 提示我給你!

    1.

    thermoplastic can melt when heated. there're no cross-linking between long polymer molecules; vice versa for thermosetting plastic.

    ethene and propene undergo addition polmerization, forming long chains of molecules.

    IS there any crosslinking between the molecules?

    by collecting the unused plastic, as it's thermoplastic, it can be melted and molded into something new, thus recycling it.

    2.

    Go to 6.

    3.

    Think of the uses of petroleum. loop up your textbook and see if petroleum can be replaced by something else for its function?

    4.

    CAN be or SHOULD be?

    if CAN be, one reason is mentioned in Q.1;

    if SHOULD be, think of the environmental problems caused by disposal of plastics, e.g. non-biodegradable.

    5.

    Non-biodegradable. when dumped into landfills, even after hundreds of years, it is still not decayed... !

    6.

    a. acidic gas into rainwater...

    b. HCl is acidic, so scrubbing the flue gas into alkaline solutions like sodium hydroxide will remove HCl...

    c. first calculate molecular mass of a repeating unit of PVC, then determine no. of mole of PVC repeating unit;

    since one unit contains one Cl, no. of mole of Cl, thus no. of mole of HCl and its mass can be calculated.

    ps. molecular mass of a repeating unit = 12x2 + 1x3 + 35.5 = 62.5 g/mol

    7.

    loop up your textbook, it's explicitly stated clearly.

    well, progress of addition polymerization (no. of polymerization reaction per polystyrene molecule) is difficult to control..

    資料來源: Your textbook!
還有問題嗎?立即提問即可得到解答。