Form 4 Science Energy and Chemical Reaction

1. Simple Cell & Chemical Cells

2. Battery A device that stores chemical energy that is later converted to electricity Some batteries may consists of 1 single simple cell with 2 electrodes and an electrolyte. When two different metal plates are dipped into an electrolytes, a flow of electron occurs from the more reactive metal to the less reactive metal. Electricity is produced. Other batteries consist of two or more simple cells arranged in series to increase the voltage.

3. Simple Voltaic Cell Consists of 2 different metals that are immersed into an electrolyte

4. Simple Voltaic Cell component aaa Electrodes, 2 different metals

8. Can be replaced by galvanometer, voltmeter or ammeterElectrodes, 2 different metals electrolyte, Can be replaced by sodium chloride solution or dilute nitric acid Chemical Energy --- Electrical Energy

9. Reactivity Series and cell voltage Negative electrode Potassium Sodium Calcium Magnesium Aluminium Carbon Zinc Iron Tin Lead Copper Mercury Silver Gold Magnesium Zinc Iron Tin Lead Copper Silver Reactivity decrease Lower Voltage Higher Voltage Positive electrode

10. How Voltaic Cell works? http://www.youtube.com/watch?v=yZduvq1ewsU http://www.youtube.com/watch?v=MYoj9N-qvX0&feature=related

12. Dry cells Produces 1.5 V Used in: radio, pockets calculators, torch, and electrical shavers (+): easy to carry (-): cannot be recharged

13. Lead-acid accumulator Supplies 12 V, consists of 6 lead-acid cells connected in series Uses in : car battery (+): can be recharged (-): heavy electrolyte spills over easily

14. Alkaline battery 1.5 V Used in: watches, torch, radios, electrical shavers and toys (+): long lasting (-): cannot be recharged more expensive

15. Silver oxide-zinc (Mercury cell) Produces 1.2 V Shaped like a button Used in: watches, camera (+): long lasting (-): cannot be recharged

16. Nickel-Cadmium battery Can be recharged Used in: mobile electrical devices such as mobile phones and drills (+): can be recharged (-): Expensive

17. Simple Voltaic Cell Consists of ______________metals that are immersed into ______________