1 Temperature and Thermal Energy Kinetic Theory of Matter The motion of the particles in matter is described by kinetic theory of matter. Matter is composed of particles that are atoms, molecules, or ions that always are in random motion. The reason for this is that all matter has ENERGY.
Energy Energy appears in many forms Potential Energy: Stored energy E.g. elastic pulled back and ready to be shot. Kinetic Energy: Energy of motion Examples??
When motion of particles increases, so does the temperature When motion of particles decreases, so does the temperature Temperature indicates the average speed of particle motion in a substance
1 Temperature and Thermal Energy Temperature The temperature of a substance is a measure of the average kinetic energy of its particles. The SI unit for temperature is the Kelvin (K).
Thermal Energy Energy associated with hot objects What gives off thermal energy?
Temperature vs. Thermal Energy Temperature = A measure of the average kinetic energy of the particles in a material. Thermal Energy = The total energy of all the particles in a material. What is the difference??
1 Temperature and Thermal Energy Thermal Energy The sum of the kinetic and potential energies of all the particles in an object is the thermal energy of the object.
1 Heat Temperature and Thermal Energy Heat is thermal energy that flows from something at a higher temperature to something at a lower temperature. Heat is a form of energy, so it is measured in joules.
1 Question 1 Section Check How is temperature related to kinetic energy?
1 Answer Section Check Temperature is a measure of the average kinetic energy of the particles in an object or material. As the temperature increases, the average speed of the particles increases.
1 Question 2 Section Check How does thermal energy differ from kinetic energy? Answer Thermal energy is the sum of the kinetic and potential energy of all the particles in an object.
States of Matter Four States of Matter Solid State The particles of a solid are packed closely together and are constantly vibrating in place. The attractions between particles are strong and solids have a fixed volume and shape.
Liquid State States of Matter The attractive forces are strong enough to cause particles to cling together. Liquids have a definite volume, but not a definite shape.
Gas State States of Matter In a gas the forces between particles are so weak that the particles no longer cling together. Gases do not have a definite shape or volume.
Plasma State States of Matter The most common state of matter in the universe is the plasma state. Plasma is matter consisting of positively and negatively charged particles and does not have a definite shape or volume.
States of Matter Changing States Melting The temperature at which a solid begins to melt is its melting point.
States of Matter Changing States Melting The temperature at which a solid begins to melt is its melting point. The amount of energy required to change a substance from a solid to a liquid at its melting point is known as the heat of fusion.
Freezing States of Matter The heat of fusion is also the energy released when a liquid freezes. The melting point is the same temperature as the freezing point. Once a liquid is frozen, the attractive forces are strong enough that the particles form an ordered arrangement.
Vaporization States of Matter Vaporization occurs as liquid changes into a gas. Vaporization that occurs at the surface of a liquid is called evaporation. Evaporation causes the temperature of the liquid to decrease.
Boiling States of Matter The boiling point of a liquid is the temperature at which the pressure of the vapor in the liquid is equal to the external pressure acting on its surface.
States of Matter 2 Condensation The heat of vaporization is also the amount of energy released during condensation. This graph shows the temperature change of water as thermal energy is added. Temp Heat (in )
States of Matter Condensation The average kinetic energy of the water molecules doesn t change. The temperature remains constant during melting. Temp Heat (in )
States of Matter Condensation 2 After the liquid water has changed completely into a gas, the temperature of the gas increases Temp as energy is added. Heat (in )
States of Matter Thermal Expansion The Thermal Expansion of Matter When particles separate, an object expands. (Heat can cause this to happen). When a material cools, the particles in the material move more slowly and become closer together.
States of Matter Thermal Expansion of Liquids The forces between the particles in liquids are weaker than the forces between the particles in a solid. The same temperature increase usually causes liquids to expand much more than solids.
States of Matter Thermal Expansion of Gases In a gas, the forces between particles are much weaker than they are in liquids. Gases expand even more than liquids for the same increase in temperature.
Question 1 Section Check is a state of matter consisting of positively and negatively charged particles that exists where the temperature is extremely high. A. Gas B. Liquid C. Plasma D. Solid
Answer Section Check The answer is C. Plasma is found in the Sun, stars, lightning bolts and neon lights.
Question 2 Section Check Most materials have a specific type of geometric arrangement. A. gaseous B. inert C. liquid D. solid
Answer Section Check The answer is D. The particles in most solids align themselves in ordered geometric patterns.
Question 3 Section Check The amount of energy required to change 1 kg of a substance from a solid to a liquid at its melting point is known as the. A. heat of energy B. heat of fusion C. heat of melting D. heat of vaporization
Answer Section Check The correct answer is B. Heat of fusion causes an ice cube to become liquid water.