electrolysis with copper electrodes and baking soda electrolyte?

[kmq]

while doing electrolysis with copper electrodes and baking soda electrolyte to make copper oxide, it makes a slightly odd smell and burning the gas by putting a lighter above it makes a dark black smoke. also there are both green strands and black lumps formin in the water. im assuming that the green is copper oxide (what im after) but is the black stuff or gas dangerous? can anyone tell me what the gas is?

[rthmjohn]

Copper oxides are either red (Cu2O) or black (CuO) depending on the oxidation number of copper. In this case, your copper oxide is black (as expected). The green stuff in the water, however, is probably copper carbonate. As far as the gas coming out of the water... I would imagine that it's hydrogen gas from the electrolysis, but if it leaves a black smoke then I don't know what it could be.

[YT2095]

the Only possibility would be Oxygen starvation of the lighter Fuel, perhaps you`re getting some CO2 liberated?

that will make for incomplete combustion and give of Carbon (soot) and probably CO also.

have you tried your lighter at a similar angle and as close to another object or liquid and seen the same? It COULD be a perculiarity of the lighter itself

[woelen]

while doing electrolysis with copper electrodes and baking soda electrolyte to make copper oxide, it makes a slightly odd smell and burning the gas by putting a lighter above it makes a dark black smoke. also there are both green strands and black lumps formin in the water. im assuming that the green is copper oxide (what im after) but is the black stuff or gas dangerous? can anyone tell me what the gas is?

Which gas do you light? At the anode or at the cathode? I only can imagine formation of H2 at the cathode. Are you sure that the soot is not from the flame of the lighter? Just by keeping it upside down or in a confined space with limited ventilation you may have a sooty flame. I hardly can imagine that you get a hydrocarbon from this electrolysis process.

 

I would expect formation of H2 gas at the cathode and formation of copper (II) carbonate or some copper (I) species at the anode.

 

The green stuff almost certainly is a copper (II) species, but not pure copper (II) oxide. Copper (II) oxide is black. Copper (I) oxide is red, orange or even yellow, exact color depending on how finely it is divided and on the amount of water, incorporated into the compound.

 

I think that the green stuff is a mix of copper (II) carbonate, oxide and hydroxide. Try heating the stuff. It probably turns black also.

[rthmjohn]

In fact, it is impossible to form a hydrocarbon from electrolysis of H2O. The black soot is most definitely from your lighter or an impurity in the water that you are unaware of.

[kmq]

thanks for the replies, everyone. So contrary to what everyone has always told me, the green stuff you sometimes find on old pennies isnt actually rust?

 

Also, if i replace the anode with a carbon rod (ie pencil core), then again use baking soda as an electrolyte and a 14 vdc power supply and after a day or so boil off all the water, will I be left with reasonably pure copper oxide, or will there be too many impuraties from the baking soda? (I'm thinking at least 90% pure copper oxide)

[jdurg]

It's impossible for there to be rust (iron oxide) on a penny as there is no iron whatsoever in pennies. Only in 1943 were pennies made with iron. Every other year has been copper and/or zinc with a teency percentage of tin.