Topic 2: Thermal physics Flashcards
(44 cards)
What are the distinguishing properties of solids, liquids, and gases?
Solids: Fixed shape, fixed volume, particles tightly packed, vibrate in place.
Liquids: No fixed shape, fixed volume, particles close but move past each other.
Gases: No fixed shape or volume, particles far apart, move freely.
What are the terms for the changes in state between solids, liquids, and gases?
Melting: Solid to liquid.
Freezing: Liquid to solid.
Boiling: Liquid to gas.
Condensation: Gas to liquid.
How does the motion of particles relate to temperature?
As temperature increases, the motion of particles increases. The particles move faster and spread further apart, causing expansion.
What is Brownian motion?
The random motion of particles in a suspension, such as smoke or pollen grains, observed under a microscope, which supports the kinetic particle model of matter.
How does gas pressure relate to particle collisions?
Gas pressure is caused by particles colliding with surfaces, creating a force per unit area.
What happens to the pressure of a gas when temperature increases at constant volume?
The pressure increases because the particles move faster, causing more frequent collisions with the container walls.
What happens to the pressure of a gas when volume decreases at constant temperature?
The pressure increases because the particles have less space to move, leading to more frequent collisions with the walls.
What is thermal expansion?
The increase in the size of a material when it is heated, causing its particles to move more and spread out.
What are some everyday applications of thermal expansion?
Railway tracks: Gaps between tracks allow for expansion in heat.
Thermometers: Liquid expands as temperature rises, indicating the temperature.
What are the melting and boiling temperatures for water at standard atmospheric pressure?
Melting: 0°C
Boiling: 100°C
What is the difference between boiling and evaporation?
Boiling: Occurs throughout the liquid at a specific temperature.
Evaporation: Occurs at the surface at any temperature, with only the most energetic particles escaping.
How does evaporation cause cooling of a liquid?
The most energetic particles escape from the surface, leaving behind lower-energy particles, thus reducing the temperature of the liquid.
What is the effect of temperature, surface area, and air movement on evaporation?
Higher temperature, larger surface area, and increased air movement speed up evaporation.
What happens during condensation and solidification in terms of particles?
Condensation: Gas particles lose energy and come closer together to form a liquid.
Solidification (Freezing): Liquid particles lose energy and form a solid.
How does thermal conduction occur in solids?
Thermal energy is transferred by atomic or molecular lattice vibrations and by the movement of delocalised electrons in metallic conductors.
What are some good and bad thermal conductors?
Good conductors: Metals like copper and aluminum.
Bad conductors (insulators): Wood, rubber, and air.
What is convection?
The transfer of thermal energy in liquids and gases due to density differences. Warm particles rise and cool particles sink, creating a convection current.
What factors affect the radiation absorption and emission of thermal energy?
Surface color: Black surfaces absorb and emit more radiation than white surfaces.
Surface texture: Dull surfaces absorb and emit more radiation than shiny surfaces.
What is the effect of surface color and texture on thermal radiation?
Black, dull surfaces are good absorbers and emitters of thermal radiation, while white, shiny surfaces reflect more radiation.
How does thermal radiation transfer energy without a medium?
Thermal radiation transfers energy in the form of infrared radiation, and it does not require a material medium like conduction or convection.
What happens to solids, liquids, and gases when heated?
Solids: Expand slightly, vibrate more.
Liquids: Expand as particles move further apart.
Gases: Expand greatly as particles move faster and further apart.
How do particles in a solid, liquid, and gas differ in their arrangement?
Solid: Particles are tightly packed in a fixed arrangement.
Liquid: Particles are close but can move past each other.
Gas: Particles are far apart and move freely in all directions.
How does the kinetic particle model explain the behavior of gases?
The gas particles are in constant, random motion, colliding with each other and with the walls of their container, creating pressure.
What is the effect of temperature on the motion of particles in a gas?
As temperature increases, the kinetic energy of the gas particles increases, causing them to move faster and collide more frequently.
