Magnesium + Copper (II) Sulfate: Lots going on here!
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- Опубликовано: 22 янв 2022
- When we put solid Mg ribbon in the CuSO4 solution, and the reaction starts right away. Because Mg is more active than Cu the Mg replaces the Cu in CuSO4. This is a classic single displacement reaction.
Mg (s) + CuSO4 (aq) → MgSO4 (aq) + Cu (s)
If we wrote this as a net ionic equation --- really see what is happening.
The red substance, that’s the solid Copper. The Mg metal is now in the water. So this is also a redox reaction.
Mg (s) + Cu2+ (aq) → Mg2+ (aq) + Cu (s)
But what are those bubbles? There aren’t any gasses in our equation.
We actually have two reactions taking place. The single rep reaction and Magnesium reacting with water.
Mg + H2O = Mg(OH)2 + H2
Normally the reaction takes place slowly in water because a layer of MgOH2 forms on the Mg metal and slows the reaction. But the reaction of the Mg and CuSO4 is exposing Mg to react with the water. If we collected the H2 and lit it on fire it combust.
You might have noticed a change in the color of the solution. After a while all the Cu in CuSO4 has been replaced and it the red you see on the bottom. The solution is now clear. That’s because all of the aqueous Copper (II) ions are gone - the are now solid solid copper. The Mg ions dissolved in the water - they make a clear solution.
So it’s not as simple as they tell you in school!
![[4K] Displacement Reaction of Metals - Zinc in Copper (II) Sulfate - with explanation at micro level](http://i.ytimg.com/vi/6NrE6TZ8Fzw/mqdefault.jpg)
A few notes:
I've included my cat, Appa, to make it a bit more interesting. Is it working?
At the end of the video there is no Mg (s) metal left. My assumption is that the solid is the Mg(OH)2.
At 1:51 the balanced equation is not balanced. If you want to balance it just put a “2” in front of the H2O.
yes i like cats lol
I'm told the cats are very popular on the internet.
Works like a charm
Yes, I have high hopes for this video. As a scientist it's all sort of an experiment to me!
BTW Pickle Rick rocks.
You included the cat to balance reactions
Appa, the cat, is a star. More of him please ❤
Dr.b you should be given a noble prize plus I love your cat 🐱
Thanks! 🐈 🥇🐈
i love that you credit your card, and i think its important, many scientific discoveries were probably made by their cat knocking over their work
I'll say it again: your cat is dope! He is so dope that he can make his own RUclips channel and post chemistry lessons!
Hmmm, that is an interesting thought. I'll ask him what he thinks!
Thanks so much sir, for this video.
You are most welcome!
This cat looks like me during my school’s chemistry lessons)))
He does have that look, doesn't he!
Haha, mine too 😂
Great video thanks! What is the black precipitate forming during the reaction? Cupric oxide? If so, why did that happen?
Thanks this is amazing :D
Thanks!
Awesome 😎. Thanks 👍
No problem 👍
Adorable cat
Thanks!
Thanks for this explanation. I ran this in preparation for teaching a lab and was puzzled by the evolution of gas. I couldn't for the life of me figure out what the gas would be (H2 or O2, or even SH2) and why it would be produced. But this was very helpful.
Happy to help! Sometimes seemingly simple reactions aren't so simple.
Great video
That beaker is cool enough sir...love from Insha❣️
Thanks!
The cat immediately gives you a thumbs up
Thw Blue solid is copper hydroxide
As it reacts with water and becomes Mg(OH)2, it increases pH
I really love metal reactions
Agreed! There is a very visible change but it usually takes a while so you can watch.
Hi. I am 50+ years old and not good at chemistry just picking up some chemistry out of interest.
If you added an excess amount of magnesium would that ensure your liquid was just a magnesium sulphate solution with no copper in solution?
Could you then filter it to get just the liquid and then heat it to dry off the liquid. Would that end up with a magnesium sulphate powder? Regards.
Rob
It is so cool!I did it with iron,but it didnt react so much.Maybe,try it with lithium?
Interesting! I just tried putting some steel wool in with CuSO4 and there was a reaction, but no bubbles. But Iron won't react with water to form H2 gas, so that makes sense. The steel wool did quickly change color (reddish-orange). I should do a video on this reaction sometime - thanks for the idea!
Hello Sir. Then, as the precipitate, do we get a mixture of Cu and Mg ( OH )2? How can we separate them? Thanks and regards.
Yes, you are correct. The Cu is the red solid at the bottom so we could filter that out. The Mg(OH)2 seems to largely the coil at the end of the video. When I crush it at the end you can see there is no Mg metal. I would take out everything leaving the Cu at the bottom of the beaker to separate the substances. Maybe react the what is left with some HCl to convert the Mg(OH)2 to soluble MgCl2 and H2O, then pour that off leaving only the Cu.
Is it common for when you drop that solid piece of metal in the solution that the metal it swaps with takes the same shape of the solid object or was this just a coincidence?
Not usually. What I think is happening here is that some of the Mg is reacting with the water. This forms Mg(OH)2 which is insoluble and a solid. So the coil is actually Mg(OH)2 at the end of the reaction. When I crushed it at the end of the reaction it was brittle and broke apart like a salt. That is sort of what makes this such an interesting reaction.
The rest of the Mg is in MgSO4 (aq) and is dissolved in the solution at Mg2+ ions.
Appa made the video.....David :)
Appa makes all of my videos!
Good night sir and it's morning in India
Awesome, good morning (and good night for me)!
I love how the leftover solid magnesium looks like, blue with little red parts on it. Reminds me of coral reef ! But why is it actually blue? The blue in liquid was caused by Cu2+, but the solid Cu is red, so did the ions somehow also stick to that leftover solid?
I also thought about coral reefs! For the blue at the end, my thought is that some sort of Copper carbonate formed - just enough to give us that bluish color. The color matches CuCO3 (see en.wikipedia.org/wiki/Basic_copper_carbonate). Lots going on in this reaction!
Like your voice ,but the cat is stealing the attention
That happens quite often around in my home!
cat 😍😍
Purple boleh x
heyo
Hello, you're the first to comment!
No entendí
Bom dia
Bom dia para você também! Mas é noite aqui agora e escuro lá fora.
Copper sulphate looks like cooked meth 😂