評論
打印
When these two solutions are mixed, we've got
這兩種溶液混合后會得到
lead, which is our +2
鉛離子，電荷是+2
and it's going to react with iodide
它會同碘離子反應
We need 2 of them to make a neutral compound
這里需要兩個才能得到電中性
and potassium nitric
還有硝酸鉀
and we just need one nitric here
這里只需要一個硝酸根離子
So our cations and anions all switched places
陽離子和陰離子相互交換了位置
We're gonna need to balance this equation
我們需要配平方程式
Let's throw some 2s there
這里加一些2
and there
還有這里
So how can we predict which one of these two compounds
我們如何確定這兩種化合物中
is the yellow precipitate?
哪一種是黃色沉淀呢
Hundreds of years ago, chemists mixed ions together
數百年前，化學家們就混合了各種離子
and they came up with solubility tables just like this one
得到這樣的溶解性表
and this chart basically shows us when these two ions
這張表顯示出兩種離子混合時的情況
an ion from this column and this column are mixed together
將這一列和這一列的離子混合起來
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，表中記作aq，表示可溶
and if it's insoluble in water, there's an s, for solid
如果不溶于水，記作s，表示固體
So our two compounds that we want to look at are
這里我們要看的兩種化合物是
lead iodide and potassium nitrate
碘化鉛和硝酸鉀
So let's take a look
我們來看看
Potassium nitrate
硝酸鉀
We've got potassium down here at the bottom
鉀離子在下面這里
We've got nitrate here at the top
硝酸根離子在上面這里
When mixed together
混合起來后
aqueous solution, soluble in water
產物可溶于水
So it's more likely that our lead iodide would be the yellow precipitate
所以，黃色沉淀更有可能是碘化鉛
but let's see if that's true
我們來檢驗一下
Lead
鉛離子
mixed with iodide
同碘離子混合
Voila, it's a solid
看吧，它是固體
So to recap, solubility tables help chemists predict
小結一下，溶解性表能幫助化學家預測
whether or not a precipitate will form when two solutions are mixed
兩種溶液混合時是否會產生沉淀
So going back to our equation here
回到我們的方程式
The lead iodide, this is the yellow precipitate
碘化鉛，這是黃色沉淀
It's a solid
它是固態的
and the potassium nitrate is aqueous
而硝酸鉀是水溶狀態的
and even though I didn't paint my nails with this particular pigment
雖然我的指甲油不是用的這種色素
lead iodide
碘化鉛
creating nail polish colors
但創造指甲油顏色
is one of the many different things that chemists can do
就是化學家們能做的諸多事情之一
So there we go, I hope you enjoyed Midas' magic
就到這里吧，但愿大家喜歡邁達斯的魔術
and I'll see you next time
我們下次再見
