How much energy is needed for electrolysis to produce 2.5l of hydrogen?

In summary, to get 2.5 liters of hydrogen from 298K temperature, 10^5 Pa pressure, and 75% efficiency, an electric energy of 60.75 *10^3 J needs to be used."
  • #1
How much electric energy needs to be used, to get 2.5l of hydrogen, when T=298K, pressure 10^5Pa? Electrolysis happens at 5V, efficiency is 75%.

I am quite lost here. Not sure were to start. I tried finding the needed current by getting hydrogen to kg and then by comparing to 0.0104*10^-6kg/C (electrolysis). I get 21.6*10^3C.
Energy - E=21600*5*0.75=60.75*10^3J

Of course wrong.

Second try:
n(H)=PV/RT i get that hydrogen has 0.1mole=0.1g=100C to electrolyse it.
Then E=100*5*0.75=375J - WRONG
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  • #2
maybe look at the Bond dissociation energy , or the coulomb energy ,
E= q1*q2/(4pi*e*r)
q1 and q2 are the charges , e=permitivity constant r is the radius between the charges .
  • #3
cragar said:
maybe look at the Bond dissociation energy , or the coulomb energy ,
E= q1*q2/(4pi*e*r)
q1 and q2 are the charges , e=permitivity constant r is the radius between the charges .

Very much doubt it... but if you got an answer...
  • #4
you are trying eltrolzoye water or hydrogen .
  • #5
cragar said:
you are trying eltrolzoye water or hydrogen .

It doesn't say.
  • #6
well this might be the wrong way to go about this but it take
4.52eV electron volts , to break the H2 bond.
  • #7
O maybe the answer to the problem will help - 0.13MJ
  • #8
  • #9
ya man i would like to help but I’m at a loss , I don’t know why other people haven’t jumped in yet .
  • #10
If anyone is interested how to solve it read along. :smile:

"You have 0.1 mole of hydrogen gas produced (from pV=nRT)
So far so good
Multiply by Avogadro's number to find number of hydrogen molecules
Each molecule needs 2 hydrogen atoms
Each atom had a charge = 1.6 x 10^-19 C
Multiply number of atoms by this to get total charge
Energy transfer = voltage times charge, E=VQ
With only 75% efficiency the energy actually needed is this value divided by 0.75
Plug in the numbers and you get the quoted answer."

This is a quote from the solver.

1. What is electrolysis and how does it work?

Electrolysis is a chemical process that uses an electric current to separate elements or compounds into their respective parts. This is achieved by passing the current through an electrolyte solution, which causes the ions to move towards the oppositely charged electrodes. When they reach the electrodes, they undergo chemical reactions, resulting in the separation of the elements or compounds.

2. What is the role of energy in electrolysis?

In electrolysis, energy is required to provide the electric current that drives the process. The amount of energy needed depends on the type of electrolyte, the concentration of the solution, and the desired products. Higher energy levels are needed for electrolysis of more complex compounds, while simpler compounds require less energy.

3. Can electrolysis be used to produce energy?

Yes, electrolysis can be used to produce energy through a process called electrolysis fuel cells. In this process, the chemical reactions that occur during electrolysis are harnessed to produce electricity. This can be a more efficient and sustainable way to generate energy compared to traditional methods.

4. What are the applications of electrolysis in energy production?

Electrolysis has several applications in energy production, such as producing hydrogen fuel, converting renewable energy sources into storable forms, and producing metal alloys for use in batteries. It can also be used to purify and recycle metals, reducing the need for mining and reducing the environmental impact of metal production.

5. What are the advantages and disadvantages of using electrolysis for energy production?

Some advantages of using electrolysis for energy production include its ability to use renewable energy sources, its versatility in producing different types of energy (such as electricity, hydrogen, and metal alloys), and its potential for reducing greenhouse gas emissions. However, electrolysis can be energy-intensive and expensive, and it also requires a reliable source of electricity. Additionally, the production and transportation of electrolyte solutions can have environmental impacts.

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