Electrode potentials Flashcards
How is an electrochemical cell created
By joining 2 different half cells together
With electrochemical cells, what is needed to join the 2 half cells together
A wire
In electrochemical cells what does the voltmeter measure
The potential difference between the 2 half cells
Do electrons flow from a more reactive metal to a less reactive metal, or from a less reactive metal to a more reactive metal
From a more reactive metal to a less reactive metal
What is observed when the half cell loses the electrons
The electrode becomes thinner
What time of reaction is it when the half cell loses electrons and the electrode becomes thinner
Oxidation
What type of reaction occurs when the half cell accepts electrons and the electrode gets thicker
Reduction
What is the usual compound that creates a salt bridge
Potassium nitrate
What is the electrode potential measured in
Volts
What does the electrode potential tell us
How easily the half cell gives up electrons
When writing electrochemical cell equations, in what form at the equations written
In reduced form, so electrons are always on the left hand side
When given the electrode potential values, what does the more negative value indicate( oxidation or reduction)
Oxidation
When given the electrode potential values, what does the most positive value indicate (oxidation or reduction)
Reduction
What does SHE stand for
Standard hydrogen electrode
What is the electrode potential of SHE
O volts
When setting up a SHE, what are the conditions underwhich hydrogen enters the the system
- 298 K
- 100 kPa
What are the conditions when comparing electrode potential values
- Temp: 298 K
- Pressure: 100 kPa
- Concentrations of ions at 1 moldm^-3
What does the SHE allow us to find
The standard electrode potential of other half cells
When given a table of standard electrode values, what is the most powerful oxidising agent
The most positive standard electrode value
When given 2 equations and the electrode potential, which reaction would go forward
The equation with the more positive electrode potential
What does the electrode potential say
How much energy is released
When drawing electrochemical cells what are the features that you must include
- 2 half cells
- Wire
- Voltmeter
- Salt bridge
- 2 Electrodes
- The electrodes must be under the water
If the half cell is a metal, what is the electrode made of
The same metal
e.g. Fe2+ +2e- -> Fe
use a Fe electrode
If neither half cells include a metal, what electrode should you use
- An inert metal like platinum
- Or graphite
