1 / 10

Electrochemistry

Electrochemistry. Electrochemistry. The study of the interchange of chemical and electrical energy Redox reactions OILRIG Oxidation – loses electrons Reduction – gains electrons. Galvanic Cells. Anode – electrode at which oxidation occurs Cathode – electrode at which reduction occurs

neona
Download Presentation

Electrochemistry

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Electrochemistry

  2. Electrochemistry • The study of the interchange of chemical and electrical energy • Redox reactions • OILRIG • Oxidation – loses electrons • Reduction – gains electrons

  3. Galvanic Cells • Anode – electrode at which oxidation occurs • Cathode – electrode at which reduction occurs • Electrons flow from anode to cathode • Salt bridge is necessary so no buildup of charge occurs • Goal of an electrochemical cell is to get cell voltage or emf (Ecell) • Electromotive force • Pushes the current through cell • Volt – unit of electrical potential

  4. Cell Notation • Zn(s) | Zn2+ (1M) || Cu2+ (1M) | Cu(s) Anode Salt Bridge Cathode • Written in order of electron flow • Standard conditions – 1 atm and 1M solution

  5. Measured voltage of a cell is determined by the half-reactions taking place • Half-reactions all have an electrode potential (E°) and by adding these together, we get the emf (voltage) of the cell = Ecell • All E° are referenced to a SHE (standard hydrogen electrode) • SHE E° = 0

  6. Example Zn(s)  Zn2+ + 2e-E° = 0.76 V 2e- + Cu2+ Cu(s) E° = 0.34 V Zn(s) + Cu2+  Zn2+ + Cu(s)E°cell = 1.10 V

  7. E° - What does it mean? • Positive E° indicates electrons flow as indicated • If negative, both half-reactions need to be reversed • Need one reduction/oxidation • +E°cell = spontaneous • -E°cell = not spontaneous • Reverse is spontaneous • For half-reactions – the more positive E° is, the more likely it is to happen and • The more negative E° is the more likely the reverse is to happen

  8. 17.1 Example • Consider a galvanic cell based on the reactionAl3+(aq) + Mg(s) Al(s) + Mg2+(aq) • Break apart into half reactions • Give the balanced cell reaction and calculate E°

  9. 17.2 Example • Describe completely (E°, balanced reaction, schematic diagram) the galvanic cell based on the following half-reactions under standard conditionsAg+e- AgFe3+ e- Fe2+

More Related