chap 2 Flashcards
what is the kinetic particle theory?
all matter is made up of tiny particles and these particles are in constant random motion
what is the characteristics of solids?
- particles are very closely packed in an orderly manner
- attractive forces between particles are very strong
-kinetic energy of particles is very low - particles vibrate and rotate about their fixed positions
what is the characteristics of liquids?
- particles are closely packed in a disorderly manner
- attractive forces between particles are less strong
- kinetic energy of particles is low
- particles slide past one another freely throughout the liquid
what is the characteristics of gas?
- particles are very far apart in a disorderly manner
- attractive forces between particles is very weak
- kinetic energy of particles is high
- particles move quickly and randomly in any direction
what happens when a substance melts?
it changes from the solid state to the liquid state. (solid state) thermal energy is converted to kinetic energy of the particles. particles vibrate and rotate faster about their fixed positions. the temperature of the substance increases. (solid-liquid state) thermal energy is absorbed from the surroundings and the temperature of the solid is at its melting point. the particles with increased energy can overcome the forces of attraction in the solid state. the orderly packing arrangement of the particles is disrupted. both solid and liquid are present during the melting process. the temperature remains constant throughout the melting process until all the substance has melted. (liquid state) after all the solid has melted at point c , thermal energy is again converted to kinetic energy of the particles. the particles can move freely throughout the liquid. the temperature of the liquid increases beyong melting point
what happens when a substance freezes?
(liquid state) kinetic energy of the particles is converted to thermal energy which is transferred to the surroundings. with less kinetic energy, the particles slow down. the temperature of the liquid decreases. (solid-liquid state) the particles lose energy to the surroundings until it reaches the freezing point. the particles with less energy are drawn closer together by the forces of attraction between them. the particle becomes more orderly. both solid and liquid are present during freezing. the temperature remains constant throughout the freezing process until all the liquid has solidified. (solid state) after all the liquid has solidified, kinetic energy of the particles is again converted to thermal energy and transferred to the surroundings. particles can vibrate and rotate about their fixed positions. the temperature of the solid decreases below the freezing point.
when and how does evaporation occur?
-occurs at temperatures below boiling point
- occurs only at the surface of the liquid
-occurs slowly
when and how does boiling occur?
- occurs only at boiling point
-occurs throughout the liquid - occurs rapidly
