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  • What would you say

    你說在過去幾世紀裡

  • is the most important discovery

    什麼是人類最重要的發現?

  • made in the past few centuries?

    是電腦?

  • Is it the computer?

    汽車?

  • The car?

    電力?

  • Electricity?

    還是發現原子?

  • Or maybe the discovery of the atom?

    我會說是這項化學反應:

  • I would argue that it is this chemical reaction:

    一個氮氣分子

  • a nitrogen gas molecule

    加上三個氫氣分子

  • plus three hydrogen gas molecules

    得到兩個氨氣分子

  • gets you two ammonia gas molecules.

    這就是哈柏法

  • This is the Haber process

    將空氣中的氮分子

  • of binding nitrogen molecules in the air

    與氫分子結合

  • to hydrogen molecules,

    或將空氣變成肥料

  • or turning air into fertilizer.

    沒有這項反應

  • Without this reaction,

    農夫僅可生產足夠

  • farmers would be capable of producing enough food

    四十億人口所需的食物

  • for only 4 billion people;

    我們目前的人口剛剛超過七十億

  • our current population is just over 7 billion people.

    所以,沒有哈柏法

  • So, without the Haber process,

    有超過三十億的人會沒食物吃

  • over 3 billion people would be without food.

    你看,氮以硝酸鹽 NO3 的形式存在

  • You see, nitrogen in the form of nitrate, NO3,

    是植物生存的一種基本營養素

  • is an essential nutrient for plants to survive.

    當作物生長,他們消耗氮

  • As crops grow, they consume the nitrogen,

    從土壤中吸收氮

  • removing it from the soil.

    土壤中的氮可經由

  • The nitrogen can be replenished

    長時間的自然施肥法補充

  • through long, natural fertilization processes

    像動物腐化

  • like decaying animals,

    但人類想以更快的方法

  • but humans want to grow food

    種植糧食

  • much faster than that.

    那麼,這就是令人沮喪的部分:

  • Now, here's the frustrating part:

    空氣的組成中有 78% 為氮

  • 78% of the air is composed of nitrogen,

    但作物不能從空氣直接利用氮

  • but crops can't just take nitrogen from the air

    因為它含有非常強的三鍵

  • because it contains very strong triple bonds,

    作物無法分解

  • which crops cannot break.

    基本上哈柏所做的

  • What Haber did basically

    是找出一種方法

  • was figure out a way

    把空氣中的氮

  • to take this nitrogen in the air

    放進土壤中

  • and put it into the ground.

    1908 年,德國化學家弗里茨·哈柏

  • In 1908, the German chemist Fritz Haber

    發展出一種化學方法

  • developed a chemical method

    以利用空氣中取之不盡的氮

  • for utilizing the vast supply of nitrogen in the air.

    哈柏發現一種方法 把空氣中的氮

  • Haber found a method

    與氫氣鍵結

  • which took the nitrogen in the air

    以形成氨

  • and bonded it to hydrogen

    然後氨可被注入土壤中

  • to form ammonia.

    在土裡快速轉變成硝酸鹽

  • Ammonia can then be injected into the soil,

    但如果哈柏法要能拿來用在

  • where it is quickly converted into nitrate.

    餵飽全世界

  • But if Haber's process was going to be used

    他必須找出一種 能快速簡易製造出氨的方法

  • to feed the world,

    為了瞭解

  • he would need to find a way

    哈柏如何達成這項豐功偉業

  • to create a lot of this ammonia quickly and easily.

    我們必須對

  • In order to understand

    化學平衡有一番瞭解

  • how Haber accomplished this feat,

    要達到化學平衡

  • we need to know something

    你的化學反應要在封閉容器下進行

  • about chemical equilibrium.

    舉例來說,你把

  • Chemical equilibrium can be achieved

    氫氣及氮氣放在封閉容器內

  • when you have a reaction in a closed container.

    讓它們反應

  • For example, let's say you put

    實驗開始時

  • hydrogen and nitrogen into a closed container

    我們有大量的氮及氫

  • and allow them to react.

    所以氨的形成

  • In the beginning of the experiment,

    以高速進行

  • we have a lot of nitrogen and hydrogen,

    但當氫及氮反應一段時間

  • so the formation of ammonia

    到快用完的時候

  • proceeds at a high speed.

    反應變慢

  • But as the hydrogen and nitrogen react

    因為瓶子裡的氮及氫變少了

  • and get used up,

    最終,氨分子會達到一種情況

  • the reaction slows down

    就是它們又開始分解

  • because there is less nitrogen and hydrogen

    成為氮氣及氫氣

  • in the container.

    一段時間後,這兩種反應

  • Eventually, the ammonia molecules reach a point

    就是產生及分解氨氣

  • where they start to decompose

    會達到相同速率

  • back into the nitrogen and hydrogen.

    當這兩個速率相等時

  • After a while, the two reactions,

    我們就說反應達到平衡

  • creating and breaking down ammonia,

    這聽起來不錯,但並非如此

  • will reach the same speed.

    尤其當你只想要

  • When these speeds are equal,

    產生一噸的氨氣時

  • we say the reaction has reached equilibrium.

    哈柏根本不想讓氨氣

  • This might sound good, but it's not

    再分解回去

  • when what you want

    但如果你就是把這項反應

  • is to just create a ton of ammonia.

    放在封閉容器裡進行

  • Haber doesn't want the ammonia

    那就是必然的結果

  • to break down at all,

    這也就是亨利·路易·勒夏特列

  • but if you simply leave the reaction

    這位法國化學家

  • in a closed container,

    可以幫忙的地方

  • that's what will happen.

    他發現

  • Here's where Henry Le Chatelier,

    如果你把達到反應平衡的系統

  • a French chemist,

    加入某項東西

  • can help.

    像是,這麼說,氮氣

  • What he found was

    這個系統會持續進行

  • that if you take a system in equilibrium

    直到再達到平衡為止

  • and you add something to it,

    勒夏特列同時發現

  • like, say, nitrogen,

    如果你增加

  • the system will work

    一個系統的壓力

  • to get back to equilibrium again.

    這個系統會試著

  • Le Chatelier also found

    回到原有的壓力

  • that if you increase

    這就像身處擁擠的房間

  • the amount of pressure on a system,

    分子愈多

  • the system tries to work

    壓力愈大

  • to return to the pressure it had.

    如果我們回頭去看我們的方程式

  • It's like being in a crowded room.

    我們會看見在左邊

  • The more molecules there are,

    左邊有四個分子

  • the more pressure there is.

    而右邊只有兩個

  • If we look back at our equation,

    所以,如果我們想讓房間不那麼擠

  • we see that on the left-hand side,

    並因而產生較小的壓力

  • there are four molecules on the left

    這個系統就會開始

  • and just two on the right.

    結合氮及氫

  • So, if we want the room to be less crowded,

    製造出較小巧緊密的氨分子

  • and therefore have less pressure,

    哈柏瞭解到為了製造

  • the system will start

    大量的氨

  • combining nitrogen and hydrogen

    他必須發明一種機器

  • to make the more compact ammonia molecules.

    可以持續加入氮及氫

  • Haber realized that in order to make

    同時也要增加壓力

  • large amounts of ammonia,

    在這平衡系統上

  • he would have to create a machine

    這也正是他所做的

  • that would continually add nitrogen and hydrogen

    今天,氨是世上產量最多的

  • while also increasing the pressure

    化學化合物之一

  • on the equilibrium system,

    每年產量粗估為 1 .31 億公噸

  • which is exactly what he did.

    亦即二千九百億磅的氨

  • Today, ammonia is one of the most produced

    這是大約

  • chemical compounds in the world.

    三千萬隻非洲象的總重

  • Roughly 131 million metric tons are produced a year,

    每頭約以一萬磅來算

  • which is about 290 billion pounds of ammonia.

    80% 生產出的氨拿來做肥料

  • That's about the mass

    其餘則使用在

  • of 30 million African elephants,

    工業及家用清潔用品上

  • weighing roughly 10,000 pounds each.

    並拿來生產其他種氮化合物

  • 80% of this ammonia is used in fertilizer production,

    譬如硝酸

  • while the rest is used

    最近的研究發現

  • in industrial and household cleaners

    半數肥料中的氮

  • and to produce other nitrogen compounds,

    沒有被植物同化

  • such as nitric acid.

    結果是,氮就以

  • Recent studies have found

    揮發性化學化合物的形式

  • that half of the nitrogen from these fertilizers

    在地球的供水及大氣中被發現

  • is not assimilated by plants.

    嚴重破壞我們的環境

  • Consequently, the nitrogen is found

    當然,在哈柏發表他的發明時

  • as a volatile chemical compound

    無法預測這個問題

  • in the Earth's water supplies and atmosphere,

    為了承接他的開創視野

  • severely damaging our environment.

    當代科學家正在尋找

  • Of course, Haber did not foresee this problem

    21 世紀的新哈柏法

  • when he introduced his invention.

    以達到同樣程度的幫助

  • Following his pioneering vision,

    卻無危險的後果

  • scientists today are looking

  • for a new Haber process of the 21st century,

  • which will reach the same level of aid

  • without the dangerous consequences.

What would you say

你說在過去幾世紀裡

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B2 中高級 中文 TED-Ed 分子 反應 化學 氫氣 空氣

TED-Ed】Haber過程--Daniel D. Dulek (【TED-Ed】The Haber process - Daniel D. Dulek)

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    稲葉白兎 發佈於 2021 年 01 月 14 日
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