Physical Science Exam 3 Study Guide. Dr. Karoline Rostamiani. Chapter 3

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1 Chapter 3 Section 1 States of Matter What is matter made of? What are the three most common states of matter? How do particles behave in each state of matter? Solids, Liquids, and Gases Materials can be classified as solids, liquids, or gases based on whether their shapes and volumes are definite or variable. A solid is a material that has a definite shape and a definite volume. A liquid is a material that has a definite volume but not a definite shape. A gas is a material that has neither a definite shape nor a definite volume. A substance is the same whether it is a solid, a liquid, or a gas. The substance is just in a different form or state. The states of matter are the physical forms of a substance. The three well-known states of matter are solid, liquid, and gas. Matter o is made up of very tiny particles called atoms and molecules o atoms and molecules act differently in each state of matter o how fast atoms and molecules move depends on the state they are in 1 P a g e

2 Solids Has a specific shape and volume Keeps its original shape and volume no matter where it is placed The particles of solid are locked into place, however they make small movements called vibrations. 2 P a g e

3 Types of solids Crystalline o Have very orderly, three-dimensional arrangement of particles. o The particles of crystalline solids are in a repeating pattern of rows o Examples Iron Diamond Ice Amorphous o Are made of particles that do not have a special arrangement o Each particle is in one place, but the particles are not arranged in a pattern o Examples Glass Rubber Wax Liquid Particles are able to move more freely It has a substance that has a specific volume, but does not have a particular shape A liquid takes the shape of its container because particles in a liquid can flow to new locations. The volume of a liquid is constant because forces of attraction keep the particles close together. 3 P a g e

4 Particles move fast enough to overcome their attraction to each other Particles can move past each other because liquids can change shape Liquids have special properties that other states of matter do not have. o Special properties Surface tension Is a force that acts on the particles at the surface of a liquid Water has a high surface tension causing it to form spherical or oval-shaped drops Gasoline has low surface tension and forms flat drops Viscosity Is liquids resistance to flow Liquids that are sticky usually have a high viscosity. The particles in these liquids have a strong attraction for each other. Gases Constant motion of particles in a gas allows a gas to fill a container of any shape or size. Has no specific shape or volume All gases take on the shape of the container they are put in, because these particles have little attraction for each other. 4 P a g e

5 Section 2 Behavior of Gases What affects how a gas behaves? What are the gas laws? Describe the three factors that affect how gases behave? Gases behave differently than solids or liquids. Gas particles have a large amount of space between them. The space that the gas particles take up is the gas's volume It's volume depends on its temperature and pressure Temperature Temperature is a measure of how fast the particles of an object are moving The faster the particles are moving the more energy they have The higher the temperature the faster gas particles move Volume The volume of an object is how much space it takes up Gas particles do not stick together. They spread out. Therefore, the volume of a gas always depends on the container the gas is in. 5 P a g e

6 Pressure The amount of force that is put on an area The number of times the particles of a gas hit the inside of their container Collisions between particles of a gas and the walls of the container cause the pressure in a closed container of gas. Factors that affect the pressure of an enclosed gas are its temperature, its volume, and the number of its particles. Gas Laws Boyle's law The volume of a gas is inversely related to its pressure when temperature stays the same. Meaning that when the pressure of a gas increases, its volume will decrease For example if the pressure of a gas doubles, the volume will be cut in half 6 P a g e

7 Charles's Law The volume of a gas is directly related to its temperature when pressure stays the same. If temperature of a gas increases, the volume of a gas will increase For example, if the temperature of a gas doubles, the volume doubles 7 P a g e

8 Section 3 Changes of State What is a change of state? What happens during a change of state? What can happen when a substance loses or gains energy? Change of state Happens when matter changes from one physical form another Energy must be added or removed in order for a substance to change its physical state. Particles of every substance move differently Melting, freezing, vaporization, condensation, sublimation and deposition are six common phase changes. A phase change is the reversible physical change that occurs when a substance changes from one state of matter to another. Energy is either absorbed or released during a phase change. During an endothermic change, the system absorbs energy from its surroundings. During an exothermic change, the system releases energy to its surroundings. Vaporization is the phase change in which a substance changes from a liquid into a gas. Vaporization is an endothermic process. Condensation is the phase change in which a substance changes from a gas or vapor to a liquid. Condensation is an exothermic process. Sublimation is the phase change in which a substance changes from a solid to a gas or vapor without changing to a liquid. Sublimation is an endothermic change. Deposition is the phase change in which a substance changes from a gas or vapor directly into a solid. Deposition is an exothermic change. Evaporation is the process that changes a substance from a liquid to a gas at temperatures below the substance's boiling point. Melting is the change of state from a solid to a liquid. Freezing is the state from a liquid to a solid. 8 P a g e

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