1 / 19

ELECTROCHEMISTRY

ELECTROCHEMISTRY. ELECTROCHEMISTRY. Process-a compound is decomposed into its constituents elements when electric current passes through an electrolyte. ELECTROLYSIS. Substance that can conduct electricity in molten/ aqueous solution Undergo chemical changes. ELECTROLYTE.

milica
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

  3. Process-a compound is decomposed into its constituents elements when electric current passes through an electrolyte ELECTROLYSIS Substance that can conduct electricity in molten/ aqueous solution Undergo chemical changes ELECTROLYTE • Conductors in the form of wires, rods, or plates. • It passes electricity through the electrolyte during electrolysis • Inert: do not take part in chemical reactions • e.g: carbon & platinum • Active : take part in chemical reaction • e.g: copper, silver, mercury • Cathode: negative terminal • Anode: positive terminal ELECTRODE

  4. ELECTROLYSIS SETUP-molten compound-

  5. Terms in electrolysis • Cation • Anion • Electrode • Inert electrode • Battery • Positive terminal • Negative terminal • Cathode • Anode • Electrolysis • Molten • Aqueous • Electrolyte • Non-electrolyte • Discharged

  6. anion cation

  7. ELECTROLYSIS OF AQUEOUS SOLUTIONS + Aqueous solution A compound water NaCl (s) NaCl solution (aq)

  8. Electrolysis of NaCl solution Anode: 4OH⁻ O2 + 2H2O + 4e⁻ Cathode: 2H⁺ +2e⁻H2 C A R B O N C A R B O N Cl⁻ Na⁺ OH⁻ H⁺ e⁻ Na⁺ Cl⁻ H⁺ OH⁻

  9. Electrolytic cell

  10. Electrochemical series (ECS) E A S I E R T O D I S C H A R G E The lower the position of an ion in ECS,the higher is the tendency of the ion to be discharged.

  11. Mari menghafal… • K.................kalau • Na...............nak • Ca.........cari • Mg...............mak • Al..................ali • Zn.................ziarah • Fe..................flat • Sn..................satu • Pb..................pada • H.................Hari • Cu............Cuti • Au..................ahad • F..............Fasha • SO............sandha • NO............Nok • K...............Kahwin • B...............Budak • I................India • OH............OH!

  12. Example: Example 1: 0.5 mol dm3 of potassium chloride, KCl solution Cations: K+ and H+ Anions : Cl-and OH- Cathode (negative electrode): H+ move to the cathode (ions are selectively discharge) Anode (positive electrode): OH- move to the anode (ions are selectively discharge)

  13. Example 2: 0.1 mol dm3 of copper(II) sulphate, CuSO4 solution Positive ions (cations): copper ions (Cu2+) and hydrogen ions (H+) Negative ions (anions): sulphate ions (SO42-) and hydroxide ions (OH-) Cathode (negative electrode): Cu2+ move to the cathode (ions are selectively discharge) Anode (positive electrode): OH- move to the anode (ions are selectively discharge)

  14. Concentration of Ions in electrolyte • Ion that have high concentration in electrolyte will be discharged.

  15. Electrolysis 2.0 mol dm-3 of lead(II)  bromide, PbCl2 solution Cathode: 2H⁺ +2e⁻H₂ Anode: 2Cl⁻Cl2+ 2e⁻ C A R B O N C A R B O N if 2 ions are placed very far apart in the ECS, the concentration aspect become insignificant. Cl⁻ Pb2⁺ OH⁻ H⁺ Pb2 Cl⁻ H⁺ OH⁻

  16. Inert electrodes: Carbon and platinum (Both of these electrodes do not react with the electrolytes or products of electrolysis) • Active electrodes: Silver, copper and nickel (Active anode ionizes and concentration of cations in the electrolyte does not change)

  17. Electrolysis of CuSO4 Cathode: Cu2⁺ +2e⁻Cu Anode: CuCu2⁺ + 2e⁻ c o p p e r C O P P e r Cu2⁺ SO42⁻ OH⁻ H⁺ Cu2⁺ SO42⁻ H⁺ OH⁻

More Related