Topic I: Redox Reactions Flashcards
(12 cards)
Redox reactions
Electron transfer reactions where reduction and oxidation occur simultaneously
Disproportionation reactions
A redox reaction wherevy an element undergoes both oxidation and reduction simultaneously
What direction do electrons flow in a voltaic cell
From the negative terminal to positive terminal
Standard electrode potential
The electromotive force between a half-cell when connected to standard hydrogen electrode under standard conditions
What does the magnitude of standard electrode potential tell us
It is a measure of the tendency of reduction
The more positive the value, the more likely reduction occurs and the higher the tendency to gain electrons
What is the formula for standard cell potential
E (cathode) - E (anode)
What does a positive standard cell potential tell you about the reaction
It is a spontaneous forward redox reaction, and a non-spontaneous reverse redox reaction
This is because a positive standard cell potential means the Gibbs Free Energy is negative
What are benefits and disadvantages of hydrogen fuel cells
Benefits
The product is just energy, so it is a cleaner source and better for the environment
Disadvantage
Hydrogen is a gas and takes up space, making storage hard
Hydrogen is explosive and dangerous
What is the rule to know what ions are deposited first at the cathode and anode
At the cathode, the cation with the most positive SEP is reduced first
At the anode, the anion with the least positive SEP is oxidised first
What does the mass of elements liberated during electrolysis depend on
The time of passing of a steady current
The magnitude of the steady current
The charge on the ion of the element
When 3 faradays are passed through a cell, how much zinc is deposited
1.5 moles
Since zinc has an ionic charge of +2, it is 3/2 moles
During electroplating, where is the object to be electroplated made to be
The object to be electroplated is made to be the cathode
