Chapter 17 Review Properties of Matter

Properties of Solids Density Amount of matter in a certain amount of space (density = mass  volume) Refers to how closely atoms or molecules are packed together A substance is most dense in the solid phase and least dense in the gaseous phase EXCEPTION: WATER!!

Properties of Solids Hardness Brittleness Elasticity Malleability Tensile strength

Density of Fluids A substance in liquid form is less dense than in the solid form (except water) Liquids layer themselves according to density Layered solution lab Why NOT to put out a grease fire with water

Buoyancy of Fluids Buoyancy – measures the upward pressure a fluid exerts on an object Archimedes’ Principle – the force exerted on an object in a liquid is equal to the weight of the fluid displaced by the object All fluids do NOT exert the same buoyant force on an object

Buoyancy of Fluids Buoyant force > object’s weight = floats Buoyant force < object’s weight = sinks Buoyant force = object’s weight = neither sinks nor floats

Buoyancy and Fluids The more fluid the object displaces, the greater the buoyant force on it (and more likely it is to float)

Charles’s Law When the temperature of a gas increases, its volume also increases (and when the temp decreases, the volume decreases) When the air inside a basketball gets warm, it takes up more space When the air inside the ball gets cold, it takes up less space

Boyle’s Law When the pressure of a gas increases, its volume decreases (and when the pressure decreases, its volume increases) When a bottle of pop is opened, the compressed gas inside spreads out, taking up all the space available

Viscosity of Fluids Viscosity – measure of the material’s resistance to flow Depends on the size and shape of the molecules Does NOT depend on density

Viscosity of Fluids For liquids, viscosity decreases when temperature increases For gases, viscosity increases when temperature increases