Electrochemical Cell or EC Cells which will generate electric current spontaneously.pptx

In this PowerPoint presentation entitled “Electrochemical Cell” explains one of the topic of Inorganic Chemistry which means, a cell which generate electric current spontaneously. This includes features about objectives of the lesson, definition itself, other features of electrochemical cell, and also derivation of formulas and solution of the topic.

1. ELECTROCHEMICAL CELL – a cell will Generate Electric Current Spontaneously. Prepared by: JAN MARK A. DALUT

2. Electrochemical Cell Objectives: Define anode, cathode, metallic path, electrolyte, electrochemical cell vs. electrolytic cell. Predict and calculate the half-reaction equation that occurs at each electrode in an electrochemical cell.

3. Brief Overview: Who invented the first electric battery? Allesandro Volta – he is an Itallian (Como, Lombardy,Italy ) physicist, chemist and a pioneer of electric science. He is most famous for his invention of electric cell , w/c people then called the “voltaic pile.”

4. Key Terms: CORROSION is usually defined as the degradation of metals due to an electrochemical process. What is Electrochemical Process? Chemical reaction – involving the transfer of electrons between two electrodes in an Electrochemical cell. Electrochemical cell – “ corrosion/galvanic cell” is a device which converts chemical energy into electric energy. Electrolytic cell – “voltaic cell” is a device can convert electrical energy into chemical cell.

5. The fundamental components in an Electrochemical cell are; ANODE (-) – metal at the anode is oxidized causing it to lose mass or corrode. CATHODE (+) – reduction takes place at the cathode and electrodes are consumed . METALLIC PATH – the electrons produced due to this reaction travel to the cathode through the metallic path. ELECTROLYTE – is the electrically conductive solution (e.g. salt solution) that must be present for corrosion to occur. Anions & Cations

6. Symbols Used in Chemical Reaction + – “reacts with” ――〉 – “ to produce, or yield” – “delta or heat” ( g ) – “gas” (s) – “solid” (l) – “liquid” ( aq ) – “aqueous” – “solid precipitate” – “evolution of gas” – “ the reaction is both/reverse”  

7. Reduction – Oxidation REDOX Reaction – (reduction – oxidation) involves the transfer of electrons between chemical species (the atoms, ions, or molecules involved in the reaction). This kind of reactions are all around us: the burning of fuels , the corrosion of metals , and even the processes of photosynthesis and cellular respiration involve oxidation and reduction. Examples of common redox are shown below. CH₄(g) + 2O₂(g) —› CO₂(g) + 2H₂O(l) (combustion of methane) 2Cu(s) + O₂(g) —› 2CuO(s) (oxidation of copper) 6CO₂(g) + 6H₂O(l) —› C₆H₁₂O₆(s) + 6O₂(g) (photosynthesis)

8. How to tell if REDOX – Reaction is Spontaneous ? E° cell: (+) = spontaneous (–) = not spontaneous Are the following reactions spontaneous as written ? Example: Silver – Copper Cell + + To read: Copper placed in a copper solution and silver placed in a silver solution. reduction at the cathode : 2[ + ] oxidation at the anode : + net equation + 2 + 2  

9. Standard Cell & Cell Potential: STEPS: Determine the cathode and anode. | ‖ | 2. Determine the overall cell reaction. 2 [ + ] 0.80v + - 0.34v + 2 + 2 E° = + 0.46 3. Determine the standard cell potential. = cathode + anode or = reduction + oxidation or reverse = 0.80v + (-0.34v) = + 0.46v (spontaneous)  

10. Calculate the cell potential of a galvanic cell that uses the two half reactions shown below. + -1.18v + + 1.92v   Solution: + - 1.18 v 2 + + 1.92 v 2 + 2 2 + 1.92 v (Reduction) + + 1.18 v (Oxidation) 2 + 2 + = 3.1 v (Spontaneous)  

11. Calculate the cell potential of a galvanic cell that uses the two half reactions shown below. + + 0.80 v + - 2.37 v   SOLUTION: 2( + + 0.80 v + - 2.37 v + + 2.37 v (Oxidation) 2 + + 0.80 v (Reduction) + 2 + = 3.17 v (spontaneous)  

12. Calculate the standard cell potential of a galvanic cell given this chemical reactions below. + + (Note: Fe = (-44v) & Ni = (-0.23v)   SOLUTION: + + 0.44 v + - 0.23 v Fe + + Ni = + 0.21 v And, that’s the simple way to calculate cell potential of a galvanic cell. So, you need to adjust the standard reduction potential in such a way that the electrons can be cancelled make sure that’s the way occurs. And when you add the cell potentials, you need to get positive answer, or else zero answer(0) . Not negative answer.  

13. Try This: Determine the reaction whether it is spontaneous or not. Given this half-reactions below, calculate the standard cell potential of galvanic cell. + + 0.80 v + 2 + 0.34 v Consider a galvanic cell based on the reaction: + + Given that; Al: (-1.66 v) & Ag: + 0.80 v + + Calculate the cell potential of the electrolytic cell according to the reaction shown below. + + + 2 + 1.09 v + + 0.77 v  

14. Summary: Components of Electric Cell An electric cell must have two electrodes and an electrolyte. An electrode is a solid conductor Electrochemical cell compost of, anode, cathode metallic path and electrolyte solution (composed of cations & anions Cathode is the electrode labelled positive. Anode is the electrode labelled negative. If the E° cell is positive , the reaction occurring spontaneous. If the E° cell is negative , the reaction occurring is non-spontaneous.

15. Thank you