States of Matter Unit

Transcription

1 Learning Target Notes Section 1: Matter and Energy What makes up matter? Matter is made of atoms and molecules that are in constant motion. Kinetic Theory of Matter A. Particles that make up matter are in constant motion. B. The higher the temperature, the faster the particles move. C. At the same temperature, more massive particles move slower than less massive particles. What is the difference between a solid, a liquid, Solid has definite shape and volume and a gas? Liquid has definite volume, but not definite shape Gas changes both volume and shape The difference between a solid, a liquid, and a gas is solids and liquids don t change volume, but gases do. What kind of energy do all particles of matter have? Plasma no definite volume or shape; electrically charged state of matter (ionized); examples: lightning, fire, the Sun KINETIC ENERGY Temperature is a measure of average kinetic energy. Thermal energy TOTAL kinetic energy; dependent on particle speed and number of particles.

2 What happens when a substance changes from one state of matter to another? Section 2: Changes of State The identity of the substance doesn t change, but the energy of the substance does change. Freezing Energy is released (liquid -> solid) Melting Energy is absorbed (solid -> liquid) Condensation Energy is released (gas -> liquid) Vaporization Energy is absorbed (liquid -> gas) Sublimation Energy is absorbed (solid -> gas) Deposition Energy is released (gas -> solid) Temperature is constant during change of state. What happens to mass and energy during physical and chemical changes? **You need to know the diagram at the bottom of page 84 Mass and energy are both conserved. NEITHER MASS OR ENERGY CAN BE CREATED OR DESTROYED! Law of Conservation of Mass Law of Conservation of Energy

3 How do fluids exert pressure? FLUID (Chapter 2): a nonsolid state of matter in which the atoms or molecules are free to move past one another, as in a liquid or a gas. Section 3: Fluids Pressure the amount of force exerted per unit area of a surface Fluids exert pressure evenly in all directions. P = F/A (Pressure = Force divided by Area) SI unit: pascal (1 N/m 2 ) What is buoyant force? All fluids exert an upward buoyant force on matter. -The upward force that keeps an object immersed in or floating on a liquid. Archimedes Principle The buoyant force on an object in a fluid is an upward force equal to the weight of the fluid that the object displaces. What happens when pressure in a fluid changes? An object will float or sink based on its density and surface area. Pascal s Principle A change in pressure at any point in an enclosed fluid will be transmitted equally to all parts of the fluid. P 1 = P 2 F 1 A 1 = F 2 A 2 What affects the speed of a fluid in motion? (Hydraulic devices are based on Pascal s Principle.) Fluids move faster through small areas than through larger areas, if the overall flow rate remains constant. Fluids also vary in the rate at which they flow. Viscosity the resistance of a gas or liquid to flow Dependent on particle attraction The more attracted the particles are the slower (more viscous) a fluid is. (Ex: Honey) Fluid pressure decreases as speed increases. Bernoulli s Principle as the speed of a moving fluid increases, the pressure of the moving fluid decreases

4 Section 4: Behavior of Gases What are some properties of gases? Gases expand to fill their containers. They spread out easily and mix with one another. They have low densities and are compressible. They are mostly empty space. Gases exert pressure on their containers. How can you predict the effects of pressure, GAS LAWS temperature, and volume changes on gases? 1. Boyle s Law relates pressure to volume At constant temperature, the volume of a gas increases as the gas s pressure decreases. If the volume decreases, the pressure increases. Inverse relationship curved graph 2. Gay-Lussac s Law relates pressure to temperature Pressure of a gas increases as the temperature increases. The pressure decreases as the temperature decreases. Direct relationship straight-line graph 3. Charles s Law relates temperature to volume Mathematical Formulas of Gas Laws Boyle s Law P 1 V 1 = P 2 V 2 At a constant pressure, volume of a gas increases as the temperature increases. If the volume decreases, the temperature decreases. Direct relationship straight-line graph Gay-Lussac s Law P 1 T 1 = P 2 T 2 The Ideal Gas Law Conversions K = C cm 3 = 1 ml 1 dm 3 = 1 L = 1000 ml Standard Conditions 0 C = 273 K 1 atm = 760 mm Hg = kpa = 101,325 Pa Charles s Law V 1 = V 2 T 1 T 2 The ideal gas law relates the variables of pressure, volume, temperature, and number of moles of gas within a closed system. PV = nrt P = pressure of the confined gas (unit: atm) V = volume of the confined gas (unit: L) n = number of moles of gas R = gas constant ( L atm/mol K) T = temperature (unit: K)

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