Electrochemical Cells Flashcards
What is the definition of electrochemical series
A list of electrode potentials in order
What will be the E° of the weakest and strongest reducing agent
Weakest - Most positive E°
Strongest - most negative E°
How do you calculate EMF of a cell
Take them away from eachother and add a + sign
How do you maintain the EMF of a fuel cell when in use
Keep the concentrations of reactants constant
State the substances and conditions needed in a standard hydrogen electrode
- H2 gas and 100kPa
- 1 mol dm^-3 and HCl
- Pt electrode and temperature of 298K
Explain how a salt bridge provides an electrical connection
Free moving Ions can move through it to maintain charge balance
Why is a high resistance voltmeter used
To stop the current from flowing in the circuit so you can measure the maximum possible potential difference
What will be the E° of the weakest and strongest oxidising agent
Weakest - Most negative E°
Strongest - most positive E°
On which sides of a half equation are the oxidising and reducing agents
Left - oxidising agents
Right - reducing agents
What’s the advantages of fuel cells
- greater efficiency
- less pollution and less CO2
What’s the drawbacks of fuel cells
- expensive
- limited lifetime
- hydrogen flammable so hard to store and transport
- toxic chemical in their production
What’s advantages to ethanol fuel cells compared to hydrogen
- can be made from renewable sources in a carbon neutral way
- less explosive and easier to store
Which half cell will be oxidised and reduced
More -ve half cell - is oxidised
More +ve half cell - is reduced
Why is a platinum electrode used
- it is unreactive
- it conducts electricity
When combining half cells, which equation do you flip the reactant some products for?
Oxidation
