From Atoms to Materials

There are three kinds of mixtures: • element/element mixture • element/compound mixture •  compound/compound mixture A physical change is a change that involves physical properties. Refer to section 13.1 for details on physical properties. physical change 物理變化 iron magnet a mixture of iron and sulphur Cutting paper Changes in shape, size, etc. Dissolving sugar in water A change from solid form to solution form Melting ice A change from solid form to liquid form Fig. 13.19 Some examples of physical changes Physical changes and chemical changes In Part A of Experiment 13.4B , we mix iron powder and sulphur powder. During this process, no new substance is formed . The mixing of iron and sulphur is an example of a physical change . Some other examples are shown below. C Fig. 13.18 Iron is attracted by a magnet, but sulphur is not. Mixtures A mixture consists of two or more pure substances that are not chemically combined together. Therefore, a mixture keeps the original properties of its constituent substances. For example, in Experiment 13.4B , iron and sulphur are mixed together to form a mixture. The mixture keeps the original properties of iron and sulphur. We can use a magnet to separate iron and sulphur from their mixture. B A mixture consists of two or more pure substances that are not chemically combined together. 49 13 From Atoms to Materials © 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