Beth works for a company that makes hydrogen fuel cells. She measures the potential difference of the cell shown. Before she sets up the cell, Beth tests each gas to check its identity. Describe the tests and the results for hydrogen and oxygen gas.
Test for hydrogen splint.
Result for hydrogen test
Test for oxygen splint.
Result for oxygen test
One mole of oxygen gas produces mole of electrons but one mole of hydrogen produces moles of electrons.
The electrons need to balance so twice as many moles of are required.
A fuel cell filled with potassium hydroxide solution works better than one filled with pure water. One reason is that potassium hydroxide solution is a better electrical conductor than pure water. Explain why potassium hydroxide solution is a better electrical conductor than pure water.
Water decomposes to produce H+ and OH- at very low concentrations so in pure water there is a low concentration of elctrolysts and therfore pure water is a poor of electricity.
Potassium hydroxide is very soluble so the concentration of the is higher and the solution is a better conductor..
What are the reactants in a hydrogen fuel cell
The fuel cell converts energy between and forms (note this is a different treatment to the one in Physics where there is a chemical potential store and an electrical transfer)
What is the name of the compound that is often used as an electrolyte?
The anode has a charge and is where occurs. This is the of electrons
The cathode has a charge and is where occurs. This is the of electrons
The electrons flow from the to the
Hydrogen will enter at the .
Oxygen will enter at the
The hydrogen is
The oxygen is
Only require O2 and H2
Do not produce CO2
Long lasting so more sustainable
Hydrogen is a gas so difficult to store
Hydrogen is explosive
Hydrogen is produced from cracking fossil fuels
Advantages
Disadvantages
