Kinetic Molecular Model of Solids and Liquids PDF

KINETIC MOLECULAR MODEL OF SOLIDS AND LIQUIDS Background Information for the Learners (BIL) In the previous lessons in General Chemistry 1, you have learned about the kinetic molecular model of gases. This activity sheet will mainly focus on the kinetic molecular model of solids and liquid...

KINETIC MOLECULAR MODEL OF SOLIDS AND LIQUIDS Background Information for the Learners (BIL) In the previous lessons in General Chemistry 1, you have learned about the kinetic molecular model of gases. This activity sheet will mainly focus on the kinetic molecular model of solids and liquids. Matter can exist in three main different states: namely, solid, liquid, and gas. The most common example of which is water. You only have to think about water to appreciate how different the three states of matter are. Steam bathing, drinking, and ice skating are all done in contact with water in its various forms. But how do these states of matter differ with each other? Understanding the kinetic molecular model of the three states will answer this question. What is Kinetic Molecular Theory? The kinetic-molecular theory is a theory that explains the states of matter and is based on the idea that matter is composed of tiny particles that are always in motion. The theory helps explain observable properties and behaviors of solids, liquids, and gases. An application of the theory is that it helps to explain why matter exists in different phases (solid, liquid, and gas) and how matter can change from one phase to another.  The state of a substance depends on the balance between the kinetic energy of the individual particles (molecules or atoms) and the intermolecular forces. The kinetic energy keeps the molecules apart and moving around, and is a function of the temperature of the substance. The intermolecular forces are attractive forces that try to draw the particles together. Postulates of Kinetic Molecular Theory The Kinetic Molecular Theory (KMT) is based on a series of postulates. Some of the postulates of KMT are as follows: 1. Matter is made of particles that are constantly in motion. This energy in motion is called kinetic energy. 2. The amount of kinetic energy in a substance is related to its temperature. Increased temperature means greater speed. 3. There is space between particles. The amount of space in between particles is related to the substance's state of matter. 4. Phase changes happen when the temperature of the substance changes sufficiently. 5. There are attractive forces in between particles called intermolecular forces. The strength of these forces increase as particles get closer together. KMT of Liquids and Solids The principal difference between the condensed states (liquids and solids) and the gaseous state is the distance between molecules. In a liquid, the molecules are so close together that there is very little empty space. Thus, liquids are much more difficult to compress than gases, and they are also much denser under normal conditions. Molecules in a liquid are held together by one or more types of attractive forces. A liquid also has a definite volume, because molecules in a liquid do not break away from the attractive forces. The molecules can, however, move past one another freely, and so a liquid can flow, can be poured, and assumes the shape of its container. In a solid, molecules are held rigidly in position with virtually no freedom of motion, so they only vibrate only about fixed positions. There is even less empty space in a solid than in a liquid because their particles are tightly packed. Thus, solids are almost incompressible and possess definite shape and volume. This is due to stronger intermolecular force of attraction compared to liquids. Change in phase: The figure shows the orientation of particles in each state and the direction of phase change due to addition and removal of https://www.siyavula.com/read/science/grade-8/particle-model-of-matter/06- particle-model-of-matter?id=toc-id-4 kinetic energy. Learning Competency: Use the kinetic molecular model to explain properties of liquids and solids (STEM_GC11IMFIIIa-c-99)