P6 Density Flashcards
Describe how the arrangement of motion of particles of a substacne change when substance changes from liquid to solid state
particles in liquid move at random in contact with each other,
particles in solid hold each other together in fixed shape and vibrate about mean positions,
when liquid cools and temperature falls, particles move slower,
until slow enough for forces of attraction between them to bond them together in a fixed shape
If a gas was cooled without changing its volume, write and explain how its pressure would change
pressure falls because internal energy of molecules decreases and average speed decreases,
so collide less often with surface of container,
when they collide with surfaces , individual impacts exert less force on surface,
so total force per unit area molecules exert on surface (i.e., gas pressure) reduced
