Flashcards
The Kinetic Particle Model
Flashcards do conjunto (15)
- 1Kinetic particle model- Matter consists of small particles
- They are in constant rapid motion or vibration
- Average velocity of particles (kinetic energy) is proportional to the temperature of the substance - 2Particle movement- Kinetic energy is due to movement
- Particle movement increases = greater kinetic energy
- E.g. translational (straight lines), rotational (rotates about centre of mass), vibrational (moves towards/away from centre of mass) - 3Particle position- Potential energy is due to particles’ positions
- Distance between particles increases = greater potential energy
- PE in gases > PE in liquids > PE in solids
- To increase PE, energy must be supplied to overcome intermolecular forces (so particles can move more freely) - 4Solid state- Molecule arranged in regular pattern (lattice)
- Vibrate backwards/forwards but are held in positions by attractive forces and cannot move around - 5Melting- At melting point, vibrations are so violent that lattice breaks down
- Heat is absorbed without change in temperature (heat is used to free molecules from lattice forces)
- Molecules gain potential energy and are free to move around (becomes liquid) - 6Liquid state- Molecules same distance apart but free to move around - liquid can pour and adopt shape of container
- Still a force of attraction, so liquid has definite surface - 7Boiling- At boiling point, molecules leave liquid and become gas
- Temperature is steady (heat is used to free molecules from forces of attraction) - 8Gasesous state- Molecules much further apart and move faster
- Almost no force of attraction
- Move out to fill container; pressure is caused by force of molecules hitting container walls - 9Absolute zero- ‘Lowest possible temperature’ is -273ºC
- So much heat is removed that particles stop moving (no kinetic energy)
- Kelvin scale (K) is also called absolute scale of temperature as it starts at absolute zero
- Celsius to Kelvin: + 273ºC - 10Temperature- Measure of the average kinetic energy of particles in a substance
- Determines direction of heat flow - 11Thermometer- Relies on change in physical property of a material used in the thermometer as temperature changes
- E.g. regular expansion of a liquid (mercury or alcohol) - 12Kinetic energyThe energy a body possesses due to its motion
- 13Thermal equilibrium- Occurs when two isolated systems at different temperatures come into contact and final temperature is same for both systems
- At thermal equilibrium there is no net transfer of energy from system to system - 14Law of conservation of energyEnergy can be neither created nor destroyed. It can change forms and flow from one place to another
- 15Internal energy (aka thermal energy)- Sum of KE and PE of particles in a system
- Impossible to measure (can only measure change in energy)
- Different phases of same substance at same temperature contain different amounts of internal energy e.g. 1 g of liquid water at 0ºC contains more internal energy than 1 g of ice at 0ºC
Informações
- Descrição
- The kinetic particle model describes matter as consisting of particles in constant motion, except at absolute zero
- Criado por
- Mel M
- Visualizações
- 92
- Avaliação