Make Copper Sulfate from Copper and Sulfuric acid (3 ways)


Uploaded by NurdRage on 25.07.2009

Transcript:
Greetings fellow nerds.
In this video we're going to make copper sulfate
for those of you interested in the chemistry.
And we'll show you three ways of doing it.
In all these methods we'll need concentrated sulfuric acid
that we already made in a previous video.
In the first method.
Get a solution of 10 mL of 30% hydrogen peroxide
and add 3 mL of concentrated sulfuric acid.
It's going to heat up a lot so be very careful.
Now drop in 3 g or so of copper metal.
This can be obtained from pipes or wires.
The copper metal will dissolve to form copper sulfate.
While very simple, this method is not very efficient
since a lot of the hydrogen peroxide decomposes.
A better method is to use nitric acid as your oxidant.
First get 30mL of water and add 3mL of nitric acid
along with 5mL of sulfuric acid.
Then add in 6 grams or so of copper metal.
The reaction will produce both copper sulfate and nitrogen dioxide gas.
Because the gas is toxic this must be performed outside or in a fumehood.
When it stops fizzing it's done.
Now copper sulfate can also be made electrochemically.
Get a solution of 5 mL of sulfuric acid in 30 mL of water.
Then place in two copper electrodes made of pipe or wire.
Connect each terminal to a six volt battery or five volt power supply.
Make sure the electrodes don't touch.
I'm using a battery for demonstration
but it's cheaper in the long run to use a power supply.
Alright let me adjust the camera...
The negative electrode is generating hydrogen gas
which you can see bubbling out on the right electrode.
The positive electrode is dissolving into the sulfuric acid
as it's being oxidized by the electric current.
The copper sulfate being generated turns the solution a blue color.
This process as laid out is not very efficient
because some of the copper ions being oxidized into the solution
at the positive terminal, is diffusing over to the negative terminal
and being reduced back out of solution.
But there is actually a simple trick to get around this.
This time start with a coiled bunch of wire
and place it into the bottom of the container.
Put over an insulating tube on the end you're connecting to the battery.
This is to slow the decomposition of this end and make the electrode last longer.
Connect it up to the positive terminal of the battery.
Now here's the trick,
hang your negative electrode so that it's a good distance above your positive electrode.
You'll see why in a minute.
Connect it up to the battery
and fill the cell with the dilute sulfuric acid solution.
You only want the negative electrode to bubble for best efficiency.
If both electrodes bubble then you'll need to lower voltage
or raise the top electrode even higher until the bottom electrode stops bubbling.
As it runs, most of the copper sulfate generated stays near the positive electrode.
By preventing the copper sulfate from reaching the negative electrode
the conversion efficiency is increased.
That's the trick for making copper sulfate by home electrochemistry.
Alright, no matter how you make it,
to get your solid copper sulfate you can boil down the mixture.
Since there is going to be excess sulfuric acid the mixture will never boil dry.
But the the copper sulfate will precipitate out right about... now.
Here is the fine copper sulfate powder in sulfuric acid.
Just filter it off and recycle the acid to make more copper sulfate.
If you want very large crystals,
just let the mixture evaporate instead of boiling it
and eventually you'll get these nice large crystals of copper sulfate.
We'll be using copper sulfate in upcoming videos so please subscribe, rate and comment.