RedOx Reactions & Phase Changes

In summary, the conversation discusses the occurrence of phase changes in electro-chemical cells and RedOx reactions in solutes, particularly when involving the ionic form of the metal that made the electrode. While some reactions may result in a change in the state of matter from liquid to solid or gas, this is not always the case. The use of platinum in such reactions is mentioned as a special case. The conversation also mentions examples of redox reactions that occur entirely in solution or in gas phase, such as in batteries and oxyhalide ions.
  • #1
somasimple
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Hi,

In electro-chemical cells (galvanic, concentration, etc) or more generally when some RedOx reactions occur in solutes, is there always a phase change?
I mean is there always a change in the state of matter from liquid to solid or gas?
 
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  • #2
No.

Pt|Fe2+(aq),Fe3+(aq)||Ce4+(aq),Ce3+(aq)|Pt

(I haven't used cell notation in ages, chances are I did some mistake, but you should get the idea).
 
  • #3
May we say that the use of Platinum is certainly a special case?
Can I rephrase my sentence like that?
In electro-chemical cells (galvanic, concentration, etc) or more generally when some RedOx reactions occur in solutes containing the ionic form of the metal that made the electrode, is there always a phase change?
I mean is there always a change in the state of matter from liquid to solid or gas?
 
  • #4
Well, if you specifically ask for a reaction in which the reactant and product are in different phases then the phase change seems inevitable, doesn't it?
 
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  • #5
You're The Man!
 
  • #6
There are plenty of redox reactions that occur entirely in solution, particularly among transition metal ions. Oxyhalide ions like bromate and hyopchlorite also effect oxidations without a phase change. A butane lighter is an example of gas-phase redox chemistry.

Batteries are a special case, since you almost always have a metallic anode.
 

FAQ: RedOx Reactions & Phase Changes

Question 1: What is a RedOx reaction?

A RedOx (reduction-oxidation) reaction is a chemical reaction in which one substance transfers electrons to another substance. The substance that donates electrons is called the reducing agent, while the substance that accepts electrons is called the oxidizing agent. This exchange of electrons can result in a change in oxidation states of the elements involved.

Question 2: How do I balance a RedOx equation?

To balance a RedOx equation, you need to follow these steps:

  1. Identify the oxidation states of all elements involved in the reaction.
  2. Write the half-reactions, one for the reduction and one for the oxidation, and balance the number of atoms on each side.
  3. Balance the charge by adding electrons to the appropriate side.
  4. Make sure the number of electrons transferred in each half-reaction is the same, and then add the two half-reactions together.
  5. Check that the number of atoms and the charge are balanced on both sides of the equation.

Question 3: What is a phase change?

A phase change is a physical change in which a substance transitions from one state of matter to another. The three main phases of matter are solid, liquid, and gas. Examples of phase changes include melting, freezing, evaporation, and condensation.

Question 4: How does temperature affect phase changes?

The temperature at which a substance undergoes a phase change is dependent on the intermolecular forces between its particles. When the temperature of a substance reaches its melting or boiling point, the intermolecular forces are weakened enough to allow the substance to change phases. This means that the temperature will remain constant during the phase change until all of the substance has transitioned to the new phase.

Question 5: Can a RedOx reaction occur during a phase change?

Yes, a RedOx reaction can occur during a phase change. For example, when a metal is oxidized, it may release heat as it transitions from a liquid phase to a solid phase. This heat release is a result of the RedOx reaction that is occurring during the phase change. Additionally, some phase changes may involve the transfer of electrons, such as in the case of electrolysis where an electric current is used to drive a RedOx reaction and produce a phase change.

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