Redox And Standard Electrode Potential Flashcards
What are the standard conditions ?
298K
1.0 mol dm-3
1 atm
What does oxidation involve?
Loss of electrons
Oxidation is one part of the redox process.
What does reduction involve?
Gain of electrons
Reduction is the counterpart to oxidation in redox reactions.
What acronym can be used to remember oxidation and reduction?
OILRIG
stands for ‘oxidation is loss, reduction is gain’.
What is a redox reaction?
A reaction where oxidation and reduction occur simultaneously
In these reactions, one species loses electrons while another gains them.
What is the role of electrochemical cells in redox reactions?
They use redox reactions for electron transfer, creating a flow of electrons
This flow generates an electrical current between electrodes.
What does the oxidation number represent?
The oxidation state of an element or ionic substance
It helps determine the electron transfer in reactions.
What is the oxidation number of an element in its elemental form?
Zero
This is a fundamental rule for assigning oxidation numbers.
In a neutral compound, what do the oxidation numbers add up to?
Zero
This rule helps in calculating oxidation states in compounds.
In a charged compound, what do the oxidation numbers add up to?
The total charge of the compound
What is the oxidation number of hydrogen in most compounds?
+1
The exception is in metal hydrides where hydrogen has an oxidation number of -1.
What is the oxidation number of oxygen in most compounds?
-2
The exceptions are peroxides and when bonded to fluorine, where it is -1.
What oxidation number do all halogens typically have?
-1
This rule applies unless they are bonded to oxygen or other halogens.
What oxidation number do Group I metals have?
+1
This is a consistent rule for these metals in compounds.
True or False: The oxidation number of sulfur in the compound Na2S must total zero.
True
This is based on the rule that oxidation numbers in a neutral compound add up to zero.
What are the main components of most electrochemical cells?
Two solutions with metal electrodes and a salt bridge
The solutions typically contain metal ions
What is the function of a salt bridge in an electrochemical cell?
To carry the flow of charge between solutions without interfering with the reaction
It typically contains unreactive ions.
Which salts are commonly used in the salt bridge?
KNO₃ or KCl
These salts are chosen for their ability to remain unreactive in the electrochemical environment.
What is a half-cell in the context of an electrochemical cell?
Each solution in the cell
Each half-cell contains a metal electrode and its corresponding metal ion solution.
What are the components of the example electrochemical cell provided?
Copper electrode, copper sulfate solution, zinc electrode, zinc sulfate solution
This illustrates a typical galvanic cell setup.
What is a half-cell in a chemical cell?
Each solution is a half-cell which together makes up the full chemical cell.
What does the cell potential indicate in a chemical cell?
It indicates how it will react, either as an oxidation or reduction reaction.
What are half equations used for?
They are used to show the separate oxidation and reduction reactions that occur in a redox reaction.
What must be balanced in half equations?
They must be balanced in terms of the species present and the charges of the species on both sides of the equation.
What is the first step in balancing half equations?
Balance all species excluding oxygen and hydrogen.
How do you balance oxygen in half equations?
Using H₂O.
How do you balance hydrogen in half equations?
Using H⁺ ions.
What is used to balance charges in half equations?
Using e (electrons).
What is the overall redox reaction when combining half equations?
The number of electrons must be the same for both half equations, which can be achieved by scaling up the number of moles
This ensures that the electrons lost in oxidation match the electrons gained in reduction.
In standard cell representation, where is the half-cell with the most negative potential placed?
On the left
This positioning is crucial for correctly representing the flow of electrons.
What goes next to the salt bridge in a standard cell representation?
The most oxidised species from each half-cell
This placement helps indicate the direction of electron flow.
How is a salt bridge represented in standard cell representation?
Using a double line
