Presentation on theme: "Notes – Changes in States of Matter Chapter 6, Lesson 2."— Presentation transcript:
Notes – Changes in States of Matter Chapter 6, Lesson 2
Temperature, Thermal Energy, & Heat Changes in energy can cause matter to change from one state to another. A state change happens because of the change in motion of particles in an object. Matter Changing State
Temperature, Thermal Energy, & Heat Even when an object is not moving, the particles in the object are moving. The particles have kinetic energy, which is energy of moving things. The gas particles inside the balloon have energy because they are moving.
Temperature is a measure of the average kinetic energy of the particles in a material. Particles in matter move faster as the temperature increases. lower temperature higher temperature
Temperature, Thermal Energy, & Heat A thermometer is used to measure temperature. Particles in the thermometer’s gauge increase their speed when heated and start moving farther apart, causing the liquid in the thermometer to rise.
Temperature, Thermal Energy, & Heat Particles in a substance have potential energy. –Potential energy decreases as particles move closer together. –Potential energy increases as particles move farther apart.
The total energy of the particles of a substance is its thermal energy. –Includes kinetic energy and potential energy of a substance’s particles –A substance’s liquid state has more thermal energy than its solid state –A substance’s gas state has more thermal energy than its liquid or solid state.
Vaporization liquid → gas Thermal energy is absorbed. Particles become too spread out and the attractive forces are too weak to keep the particles close together. Vaporization can occur both at the surface and inside the liquid.
Vaporization: Boiling Vaporization that occurs inside the liquid. Boiling point refers to the temperature that boiling occurs in a substance.
The boiling point depends on the pressure exerted on the liquid. Bubbles in the liquid must form for boiling to occur. As air pressure increases, it becomes harder for the bubbles to form. The boiling point increases as air pressure increases.
Vaporization: Evaporation Evaporation is vaporization that occurs at the surface of a liquid. Evaporation occurs both at the boiling point and temperatures below the boiling point.
Vaporization: Evaporation The liquid gains thermal energy, and molecules on the surface gradually escape into the atmosphere (i.e.) water cycle, a puddle after rain, sweating to cool you down
Condensation gas → liquid Thermal energy is released. The gas particles slow down and move closer together until the attractive forces hold them together and a liquid forms.
1. The point at which a liquid changes to a gas is called ____. Amelting point Bfreezing point Ccondensation point Dboiling point 6.2 Changes in States of Matter
2. A liquid can change to a gas through ____. Aevaporation Bfreezing Cmelting Dsublimation 6.2 Changes in States of Matter
3. Thermal energy must be ____ when a liquid changes to a ____. Alost; gas Bgained; solid Clost; solid Dincreased; solid 6.2 Changes in States of Matter
4. Sublimation occurs when a solid changes into a ____. Aliquid Bgas Cplasma Dsteam
5. As air pressure ____, the ____ of a liquid increases. Adecreases; boiling point Bdecreases; freezing point Cincreases; freezing point Dincreases; boiling point
6. Adding thermal energy can ____ or ____. Alower temperature; change the state of matter Bincrease temperature; lower temperature Cincrease temperature; change the state of matter Dremove kinetic energy; change the state of matter SCI 3.e
7. One glass of water has a temperature of 30°C and another glass of water a temperature of 40°C. Which is true? AThe glass of water at 30°C has lower average kinetic energy. BThe glass of water at 40°C has lower average kinetic energy. CThe two glasses have equal average kinetic energy. Dnone of the above SCI 3.e