electrolysis Flashcards
(22 cards)
What process uses electricity to break down a substance?
Electrolysis
Electrolysis is a chemical process that uses electrical energy to drive a non-spontaneous reaction.
How can metals be extracted from molten compounds?
Using electrolysis
Electrolysis allows for the separation of metals from their compounds.
What happens to ions in ionic compounds when they are melted or dissolved?
They are free to move and can conduct electricity
This movement of ions is essential for the conduction of electricity in electrolytes.
What term describes liquids and solutions that conduct electricity?
Electrolytes
Electrolytes are crucial for electrolysis to occur.
What is the movement of positive and negative ions during electrolysis?
Positive ions move to the negative electrode and negative ions move to the positive electrode
This movement is driven by the electric field applied during electrolysis.
What is the positive electrode called?
Anode
The anode is where oxidation occurs during electrolysis.
What is the negative electrode called?
Cathode
The cathode is where reduction occurs during electrolysis.
What occurs at the electrodes during electrolysis?
Ions are discharged to produce elements
This discharge leads to the formation of different substances depending on the ions involved.
Where are metal ions attracted during electrolysis?
To the cathode
At the cathode, metal ions gain electrons and are reduced to form solid metal.
What type of electrodes are used when extracting metals from their compounds?
Inert (unreactive) electrodes
Inert electrodes do not participate in the chemical reaction and help to prevent contamination.
What is a significant drawback of electrolysis?
It uses large amounts of energy
Energy is required to melt compounds and to produce the necessary electrical current.
What is mixed with aluminium oxide to lower its melting point during aluminium production?
Cryolite
This mixture helps to reduce energy costs in the electrolysis process.
What gas is produced at the anode when aluminium oxide is electrolysed?
Oxygen
The oxygen reacts with the anode material, forming carbon dioxide, which necessitates replacing the anode.
What factors determine the ions discharged during the electrolysis of an aqueous solution?
The relative reactivity of the elements involved
More reactive elements will influence the outcome of the electrolysis.
What ions are produced when water is broken down by electricity?
Hydrogen ions (H+) and hydroxide ions (OH-)
These ions play a critical role in the electrolysis of aqueous solutions.
What is produced at the cathode if the metal is more reactive than hydrogen?
Hydrogen
This is a key consideration during the electrolysis of solutions containing metals.
What is produced at the positive electrode unless halide ions are present?
Oxygen
In the presence of halide ions, halogens are produced instead.
What are the products of the electrolysis of brine?
Hydrogen at the cathode, chlorine at the anode, and sodium hydroxide solution
These products are important in various industrial processes.
What is the term for the gain of electrons that occurs at the cathode?
Reduction
Reduction is a key concept in electrochemical reactions.
What occurs at the anode during electrolysis?
Negatively charged ions lose electrons, resulting in oxidation
Oxidation reactions are crucial in the electrolysis process.
How can reactions at the electrodes be represented?
By half equations
Half equations provide a clear representation of the electron transfer processes.
Provide an example of a half equation in electrolysis.
2H+ + 2e- → H2
This equation shows the reduction of hydrogen ions to form hydrogen gas.
