Flashcards
Electrochemistry
Cards in this deck (16)
- 1ElectrochemistryThe branch of chemistry concerned with relationships between chemicals and electrical energy. It utilises reactions that either produce or consume energy.
- 2Redox reactionsChemical reactions that involve a flow of electrons from one reacting species to the other. For every one redox reaction there must be two half reactions, neither of which can survive without the other.
Reduction + oxidation - 3Zn(s) > Zn2+ + 2e- E value: +0.76VOxidation reaction because electrons are being lost.
- 4Zn2+ +2e- > Zn(s) E value: -0.76VReduction reaction because electrons are gained.
- 5Positive and negative in a redox reaction?If the E value is positive then it will produce voltage, if it is negative then it needs to consume voltage.
- 6GalvanicIs a spontaneous redox reaction that produces energy and has a positive E value.
- 7ElectrolyticIs a non-spontaneous reaction that requires energy input and has a negative E value.
- 8Oxidation numbersThey represent the change of an atom if it was completely ionic.
- 9Factors effecting rate of reaction?Temperature, concentration, pressure, surface area and a catalyst.
- 10Collision theoryChemical collisions require the correct energy and orientation to be successful. Any change in conditions that increase the energy or number of collisions, will increase the rate of reaction.
- 11Rate of reactionThe rate at which reactants disappear. The average is defined as change in concentrations divided by the time it takes for the change to occur.
- 12Activation energyIs the minimum energy required to cause a reaction between two colliding particles.
- 13CorrosionA natural process, which converts a refined metal to a more chemically-stable form, such as it's oxide, hydroxide or sulphide product. Oxygen and water must be present for corrosion to occur.
- 14Anode and cathodeThe anode loses electrons resulting in the breakdown of the metal, while the cathode gains them. The anode will progressively be dissolved.
- 15How do you prevent corrosion?A barrier which prevents chemical contact e.g. paint, resin coating, electroplating. A sacrificial anode which is a more reactive metal.
- 16Sacrificial anodeThey are a more reactive metal that is used to prevent a less reactive metal from corroding. It will have a more negative potential.