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It's Germany in the 1930s. The Nazi party is gaining power, and two Nobel prize-winning physicists are getting very worried.
在20世纪30年代的德国，纳粹党掌权，两位获得诺贝尔奖的物理学家非常担心。
One is Max von Laue, an outspoken opponent of the Nazis. The other is James Franck, who was a target because of his Jewish heritage.
一位是马克斯·冯·劳厄，纳粹的公开反对者。另一位是詹姆斯·弗兰克，因为其犹太人的身份而成为目标。
The Nazis are seizing items of value from anyone who isn't also a Nazi. And Nobel medals are made of solid gold.
纳粹正在从非纳粹那些夺取有价值的物品。诺贝尔奖牌是由纯金制成的。
So both men sent their medals out of the country to a trusted colleague:
两人都将他们的奖牌送出国，给了一位值得信赖的同事：
a fellow prize winner Niels Bohr in Copenhagen, Denmark.
另一位丹麦哥本哈根的诺贝尔奖得主尼尔斯·玻尔。
The Nazis had made sending gold outside of Germany a crime, so this was a risky move.
纳粹规定将黄金送往德国以外的地方是犯罪，所以这一举动很冒险。
And these medals had their owner's names prominently engraved on them, so it wasn't like the bad guys weren't gonna catch on.
这些奖牌上刻着它们主人的名字，很明显，所以偷奖牌很容易被抓。
So, when Germany invaded Denmark in 1940, Bohr was desperate to hide them.
所以当德国1940年入侵丹麦时，玻尔不顾一切地把它们藏了起来。
Enter chemist George de Hevesy, who would win his own Nobel a few years later.
化学家乔治·德海韦西也将在几年后获得他的诺贝尔奖。
He was working with Bohr at the time. He turned to his knowledge of chemistry and decided to dissolve the gold.
那时他和玻尔一同工作。他借助自己的化学知识，决定溶解黄金。
This was easier said than done, because Nobel medals are made from a noble metal.
这件事说比做容易，因为诺贝尔奖牌是由贵金属制成。
A metal is considered noble when it doesn't react much with other chemicals. So it's resistant to things like rusting or being dissolved in acid.
当金属与其他化学物质反应不大时，就被认为是贵金属。所以它能抵抗生锈和酸的溶解。
Which elements are included among the noble metals depends on the context you're talking about.
这些贵金属中包含哪些远离取决于谈论的语境。
Chemists define about eight to ten noble metals based on their lack of reactivity.
化学家们根据缺乏反应性定义了大约8到10种贵金属。
Physicists, however, pay more attention to what's going on inside the atoms.
但物理学家更关注这些原子的内部情况。
They use a stricter definition: metals with full d-subshells. That refers to the configuration of their electrons.
他们使用一种更严格的定义：拥有完整d-支壳层的金属。这指的是它们电子的构型。
The classic cartoon of an atom has electrons orbiting the nucleus like planets in the solar system, but things are a bit more complex than that.
一个原子的经典动画是电子绕着原子核旋转，就像太阳系中的行星一样，但事情要比这复杂一点。
Electrons exist at different energy levels, and in differently shaped orbitals, around an atom's nucleus.
电子在原子核周围以不同的能级存在于不同形状的轨道上。
These are given different numbers and letters depending on their shape and how much energy they have.
根据它们的形状和能量大小，被它们赋予一些不同数字和字母。
Electrons at the highest energy level tend to be the ones participating in reactions, and for metals, these are in their d-subshell.
最高能级上的电子会参与反应，并且对于金属而言，这些位于它们的d-支壳层。
If that subshell is full, the metal will be particularly stable.
如果那个支壳层是完整的，那么该金属就尤为稳定。
Chemical reactions are all about swapping electrons, but that full subshell means it has a complete set already.
化学反应就是交换电子，但完整的支壳层意味着它已经有了完整的电子集。
The three metals that meet this definition are copper, silver, and gold. And even among noble metals, gold is king.
满足这一定义的三个金属是：铜、银和黄金。即便在这些贵金属中，黄金也是王者。
Along with platinum, it's usually considered the least reactive of all the metals.
黄金和铂通常被认为是所有金属中最不活泼的。
So de Hevesy had a challenge ahead of him: dissolving something that barely reacts with anything.
所以德海韦西面临着一个挑战：要溶解一个几乎对任何物质都不产生反应的物质。
He turned to a particularly potent mix of acids: one part nitric to three parts hydrochloric.
他转而使用一种特别强力的酸混合物：一比三的硝酸和盐酸。
For centuries, this concoction has been known as aqua regia, meaning "royal water".
几个世纪以来，这种混合物一直被称为王水，意思是“皇室之水”。
And it can dissolve gold because each acid has a particular role in shifting the equilibrium of the reaction.
它可以溶解黄金，因为每一个酸在改变反应平衡方面起到了有特殊作用。
See, a lot of chemical reactions don't just react to form their products, and then stop.
很多化学反应不只是生成产物，然后停止。
Some of those products go the other way to form the reactants again, so there's a balance between reactants and products in your flask.
其中一些生成物反过来又形成了反应物，所以在烧瓶里反应物和生成物之间有一个平衡。
In fact, the forward reaction doesn't always "go" very far at all. These reactions are called reversible reactions,
实际上，正向反应并不总能持续很久。这些反应被称为可逆反应，
and they will eventually reach an equilibrium point when the rate of the forward reaction is the same as the rate of the reverse.
并且最终将会在正向反应率和可逆反应率相同时到达一个平衡点。
But that equilibrium point can shift. If you use a second reaction to remove the products of the first,
但这个平衡点可以改变。如果用第二个反应来去除第一个反应的产物，
you can shift this equilibrium point and drive the reaction further than it would otherwise go.
你可以改变这个平衡点，并让反应更持久。
When the Nobel medals hit the aqua regia, the nitric acid was able to pry off just a few gold atoms in the metal to make gold ions in the solution.
当诺贝尔奖牌遇上这个王水，硝酸就能够撬开金属中的几个金原子，让它们在溶液中形成金离子。
Now, if it were just nitric acid, things would have stopped here.
如果只有硝酸，一切到此就结束了。
But the hydrochloric acid stepped in to provide chloride ions, which reacted with the gold ions to form a molecule called tetrachloroaurate.
但盐酸介入提供氯离子，氯离子和金离子产生反应行为四氯金酸盐。
This shifted the equilibrium of the first reaction by removing gold ions,
这通过移除金离子而改变了第一次反应的平衡，
and allowed the nitric acid to dissolve a little bit more of the gold metal.
并让盐酸溶解更多的黄金金属。
This continuous removal of gold ions allowed the reaction to continue until the solid gold vanished into the solution.
这种持续的移除金离子让反应得以继续，直到纯金消失在溶液中。
de Hevesy wrote that this was going down even as occupying soldiers were marching in the streets of Copenhagen.
德海韦西写道，占领军队在哥本哈根街头游行，这一过程还在进行中。
But by then, the only thing left for them to find was a glass container of the gold solution sitting in his lab.
但到那时，他们唯一能找到的就是他实验室里的一个装有金溶液的玻璃容器。
And that glass was perfectly safe from the acid. Just because aqua regia can dissolve gold,
那个玻璃不受酸的影响。王水可以溶解黄金
doesn't mean it can dissolve anything, and glass doesn't have the same vulnerability that gold does to aqua regia's two-pronged attack.
并不意味着一切皆可溶解。玻璃玻璃不像黄金那样容易受到王水的双重攻击。
The gold hid in plain sight for nearly 10 years. But it wasn't gone, just in a different form: chloroauric acid.
黄金在众目睽睽之下藏了将近10年。但它没有消失，只是形态不同：氯金酸。
After the war, de Hevesy was able to get the gold back out of the solution.
战争结束后，德海韦西将黄金从溶液中取出。
He didn't record exactly what he used, but some chemicals can shift the equilibrium so far in the other direction,
他并没有记录自己使用的物质，但一些化学家可以反方向改变这一平衡，
it drives the reaction in reverse and causes the gold to precipitate out.
它使反应发生逆转，并使黄金沉淀出来。
de Hevesy delivered the gold to the Nobel Foundation, who remade the medals using the same material and gave them back to their rightful owners.
德海韦西将黄金寄给了诺贝尔基金会，基金会用收到的材料重新制作了奖牌，并把奖牌送还给了他们的得主。
He was presented with a problem, and you could say he found a solution.
他遇上了一个难题，你也可以说他找到了一个解决办法。
Thanks for watching this episode of SciShow. If you like science, and puns, and science puns, consider supporting us on Patreon.
感谢收看本期节目。如果你喜欢科学、双关和科学双关，请在Patreon支持我们。
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