From Atoms to Materials

How may compounds be broken down? Compounds can be broken down into their constituent elements using electricity, heat or other methods. This process is called decomposition*. In the following demonstration, we shall see water broken down into its constituent elements: hydrogen and oxygen. Experiment ent Caution Ensure good ventilation. Materials and ap p a r a t u s Wear safety goggles. decomposition 分解 electrolytic cell 電解池 expanded polystyrene board water carbon electrode (positive) carbon electrode (negative) test tube Your teacher will show you a set-up for breaking down of water. 1 Switch on the power supply. Observe what happens at the electrodes. 3 Connect the two electrodes to a d.c. power supply. 2 distilled water 1 bottle sodium sulphate 1 bottle test tubes 2 electrolytic cell* (fitted with carbon electrodes) 1 d.c. power supply 1 connecting wires 2 expanded polystyrene board with two holes 1 wooden splints 2 rubber stoppers 2 gas lighter 1 13.4A Breaking water down into its constituent elements (Demo) If the decomposition is caused by electricity, it is called electrolysis. Video Breaking water down into this constituent elements Additional info To increase the electrical conductivity of water, a small amount of sodium sulphate is added to it. For a typical electrolytic cell (15 mL), 0.1 g of solid sodium sulphate is needed. Steps 44 © United Prime Educational Publishing (HK) Limited 2024 All rights reserved; no part of this publication may be reproduced, photocopied, recorded or otherwise, without the prior written permission of the Publisher. Sample