视频文本

When these two solutions are mixed, we've got
这两种溶液混合后会得到
lead, which is our +2
铅离子，电荷是+2
and it's going to react with iodide
它会同碘离子反应
We need 2 of them to make a neutral compound
这里需要两个才能得到电中性
and potassium nitric
还有硝酸钾
and we just need one nitric here
这里只需要一个硝酸根离子
So our cations and anions all switched places
阳离子和阴离子相互交换了位置
We're gonna need to balance this equation
我们需要配平方程式
Let's throw some 2s there
这里加一些2
and there
还有这里
So how can we predict which one of these two compounds
我们如何确定这两种化合物中
is the yellow precipitate?
哪一种是黄色沉淀呢
Hundreds of years ago, chemists mixed ions together
数百年前，化学家们就混合了各种离子
and they came up with solubility tables just like this one
得到这样的溶解性表
and this chart basically shows us when these two ions
这张表显示出两种离子混合时的情况
an ion from this column and this column are mixed together
将这一列和这一列的离子混合起来
is their products, the compound that they form soluble or insoluble in water
看生成的化合物是否可溶于水
If it's soluble in water, there's an aq for aqueous on the chart
如果可溶于水，表中记作aq，表示可溶
and if it's insoluble in water, there's an s, for solid
如果不溶于水，记作s，表示固体
So our two compounds that we want to look at are
这里我们要看的两种化合物是
lead iodide and potassium nitrate
碘化铅和硝酸钾
So let's take a look
我们来看看
Potassium nitrate
硝酸钾
We've got potassium down here at the bottom
钾离子在下面这里
We've got nitrate here at the top
硝酸根离子在上面这里
When mixed together
混合起来后
aqueous solution, soluble in water
产物可溶于水
So it's more likely that our lead iodide would be the yellow precipitate
所以，黄色沉淀更有可能是碘化铅
but let's see if that's true
我们来检验一下
Lead
铅离子
mixed with iodide
同碘离子混合
Voila, it's a solid
看吧，它是固体
So to recap, solubility tables help chemists predict
小结一下，溶解性表能帮助化学家预测
whether or not a precipitate will form when two solutions are mixed
两种溶液混合时是否会产生沉淀
So going back to our equation here
回到我们的方程式
The lead iodide, this is the yellow precipitate
碘化铅，这是黄色沉淀
It's a solid
它是固态的
and the potassium nitrate is aqueous
而硝酸钾是水溶状态的
and even though I didn't paint my nails with this particular pigment
虽然我的指甲油不是用的这种色素
lead iodide
碘化铅
creating nail polish colors
但创造指甲油颜色
is one of the many different things that chemists can do
就是化学家们能做的诸多事情之一
So there we go, I hope you enjoyed Midas' magic
就到这里吧，但愿大家喜欢迈达斯的魔术
and I'll see you next time
我们下次再见

视频及简介

视频简介：

魔术背后的化学系列视频展示了一些化学实验演示，这些化学实验都非常精彩有趣，创造出各种蒸汽、响声、闪光等引人注目的效果。视频中详细解释了实验背后的科学知识，通俗易懂，寓教于乐。