Chapter 8 Material on Midterm States of Matter Chapter 8 Material on Midterm

Section 1: Solids, Liquids, and Gases What are states of matter? The States of matter are the physical forms in which a substance can exist Solid Liquid Gas Plasma is a fourth state of matter that is positively and negatively charged particles Most common in universe

Section 1: Solids, Liquids, and Gases Particles of matter Matter is made of small particles called atoms and molecules Always on the move How they interact with each other determines their state of matter

Section 1: Solids, Liquids, and Gases What is a solid? A solid is the state of matter that has a definite shape and volume Particles smooshed together Can only vibrate—stuck in place

Section 1: Solids, Liquids, and Gases Types of solids Crystalline solids have a orderly, 3D arrangement in a repeating pattern Ice, diamond, iron Amorphous solids have no special arrangement Glass, rubber, wax

Section 1: Solids, Liquids, and Gases What is a liquid? A liquid is the state of matter that has a definite volume but takes the shape of its container Little space in between particles Can slide past another

Section 1: Solids, Liquids, and Gases Liquid characteristics Surface tension is an uneven force that acts on the particles at the surface of a liquid Viscosity is a measurement of a liquid’s resistance to flow

Section 1: Solids, Liquids, and Gases What is a gas? A gas is the state of matter that has no definite shape or volume Molecules move super fast Not really held together at all Vapor is the gas state of a substance that is normally a solid or liquid at room temperature

Section 1: Solids, Liquids, and Gases State of Matter Definite Shape? Definite Volume? Solid Liquid Gas

Section 2: Changes in State A change of state is the change of a substance from one physical form to another

Section 2: Changes in State Changes of state are cause by changes in energy Kinetic energy is the energy an object has due to its motion We can measure the average kinetic energy of all the particles in an object—the true definition of temperature

Section 2: Changes in State Changes of state are cause by changes in energy Potential energy is the stored energy due to interactions between particles or objects Solids have the least potential energy because their particles are so close Gases have the most potential energy because their particles are spread

Section 2: Changes in State Thermal energy is total potential and kinetic energies of an object. We can either add or remove energy to get changes of state If we add, we call it endothermic If we remove, we call it exothermic

Section 2: Changes in State The six changes of state Melting (SL) Freezing (LS) Vaporization (LG) Condensation (GL) Sublimation (SG) Deposition (GS)

Section 2: Changes in State Melting is the change of state from a solid to a liquid Adding energy to a solid increases its energy Particles move faster, move away from each other The melting point is the temperature at which a substance changes from a solid to a liquid Item Melting temperature (C) State of matter at room temperature (25C) Water 0 C Table salt 801 C Nitrogen -210 C…-159C boiling

Section 2: Changes in State Freezing is the change of state from a liquid to a solid We remove energy—molecules slow down The freezing point is the temperature at which this happens

Section 2: Changes in State Vaporization is the change of a substance from a liquid to a gas We add energy—molecules speed up Evaporation is vaporization that occurs only at the surface of a liquid Boiling is the change of a liquid to a gas (vapor) throughout the whole liquid

Section 2: Changes in State Condensation is the change of state from a gas to a liquid We remove energy—molecules slow down Condensation point is the temperature at which a gas becomes a liquid Same as boiling point

Section 2: Changes in State Sublimation is the change of state from which a solid changes into a gas without going through a liquid state We add a LOT of energy—molecules speed up a lot Dry ice Deposition is the change of state from a gas to a solid without going through the liquid state We remove a LOT of energy—molecules slow down a lot Frost

Section 2: Changes in State Change of temperature versus change of state When energy is added… Either the temperature changes OR the state changes Not both!

Section 2: Changes in State

Section 2: Changes in State When you add heat to a solid… …the temperature increases until the melting point You still add heat… …the temperature stays while the solid melts You now add heat to a liquid… …the temperature increases until the boiling point …the temperature stays while the liquid vaporizes You now add heat to a gas… …the temperature will just keep increasing!

Section 2: Changes in State

Section 2: Changes in State

Section 2: Changes in State State change Starting state Ending state Energy added or removed Endothermic or exothermic Melting Freezing Evaporation Condensation Sublimation Deposition

Section 3: The Behavior of Gases The kinetic molecular theory is an explanation of how particles in matter behave Small particles make up all matter Particles are in constant, random motion Particles collide with other particles, other objects, an the walls of their container No energy is lost when particles collide We will focus on these factors in gases

Section 3: The Behavior of Gases What factors affect how gases behave? Temperature Volume Pressure

Section 3: The Behavior of Gases Temperature Temperature is a measure of how fast the particles in an object are moving The faster the particles move, the more energy they have Increase temperature….increase pressure Increase temperatures…increase volume

Section 3: The Behavior of Gases Volume Volume is the amount of space that an object takes up Volume of a gas depends on its container Decrease volume…increase pressure…pop! Increase volume…decrease pressure

Section 3: The Behavior of Gases Pressure Pressure is the amount of force applied per unit area The more particles…the more pressure

Section 3: The Behavior of Gases

Section 3: The Behavior of Gases Gas behavior laws Boyle’s Law Involves volume and pressure Charles’s Law Involves temperature and volume Guy-Lussac’s Law Involves temperature and pressure

Section 3: The Behavior of Gases Boyle’s Law Volume (L) Pressure (Pa) 500 100 300 150 225 200 175 250 125 350 112 400 450

Section 3: The Behavior of Gases What is Boyle’s Law? Boyle’s Law states that pressure of a gas increases if the volume decreases and pressure of a gas decreases if the volume increases, when temperature is constant Inverse = opposite relationship So… As pressure increases, volume decreases As pressure decreases, volume increases

Section 3: The Behavior of Gases Charles’s Law Volume (L) Temperature (°C) 10 80 20 160 30 240 40 320 50 400 60 480

Section 3: The Behavior of Gases What is Charles’s Law? Charles’s Law states that for a fixed amount of gas at a constant pressure, the volume of gas changes in the same way that the temperature changes So… As temperature increases, volume increases As temperature decreases, volume decreases

Section 3: The Behavior of Gases Guy Lussac’s Law Volume constant Volume constant

Section 3: The Behavior of Gases What is Guy Lussac’s Law? Guy Lussac’s Law states that for a fixed amount of gas at a constant volume, the pressure of gas changes in the same way that the temperature changes So… As temperature increases, pressure increases As temperature decreases, pressure decreases