Transcript Notes
Changes in Matter Chapter 3 sections 1 and 3 Solid •Definite Shape and Definite Volume. Particles in a solid •Atoms and/or molecules are packed closely together and slightly vibrate. Types of solids • Crystalline solid: Arranged in a crystal-like, repeating pattern. • All have a distinct melting point. Types of solids cont…. • Amorphic Solid: Particles are arranged in an irregular or random pattern. • Don’t have a distinct melting point. • Example: Glass, plastic, rubber Polymers • Very large molecules made of a chain of smaller molecules • Polymers form when chemical bonds link large numbers of monomers in a repeating pattern. Polymers and Composites • The properties of synthetic polymers make them ideal starting materials for many common objects. Liquids • Takes the shape of the container that it’s in. Particles in a Liquid • Atoms and/or molecules are loosely packed together. Suspension • A mixture where particles can be seen and easily separated. • Examples: Milk, salad dressing and muddy water Viscosity The resistance of a liquid to flow. The higher the viscosity, the slower it will flow. Usually amorphic solids. BILL NYE • http://172.26.64.6/?a=50060&ch=9 • Surface tension: Molecules on the surface are only affected by those below the surface, thus causing drops of liquid to be spheres. • Start video at 5:13 Gases • Have no definite shape and no definite volume. • Very compressible. Particles in a gas • Particles are not touching, therefore the Intermolecular forces are broken. • Movement is random and independent of each other. Boyle’s Law • At a constant temperature, if the volume decreases then the pressure of a gas increases. Graph of Boyle’s Law Pressure and Temperature of gases • When the temperature of a gas increases its pressure increases and when temperature decreases pressure decreases. Charles' Law • When temperature of a gas increases its volume increases. • In other words, gases expand as they heat up and condense as they cool down. Energy and State Change • When a substance changes state: • Solid liquid gas = gaining energy • Gas liquid solid = loses energy Measuring Gases • Temperature: the measure of the motion (kinetic energy) of the particles of a substance. Measuring Gases Cont… • Pressure of a gas: The measure of the outward force divided by the surface area of the container. Increased Temperature Increased average velocity of gas particles Increased number of collisions with walls of container Increased Force per collision. Initial increase in pressure force ÷ area of container Inside pressure is greater than external pressure. Container expands Increased Volume Take out your Hot Air Balloons Lab and write down the Purpose: To Learn how the volume of a gas changes with temperature.