all matter consists of tiny particels that are in constant motion.
gas pressure
a force excerted by a gas per unit SA of an object.
Atmospheric Pressure
the collisions of of atoms and molecules in the air with objects.
barometer- how does it work?
divice that is used to measure atmosphereic pressure.
kPa or pressure is excerted on the mercury in the tube. when the pressure is higher it goes up the tube when the pressure is lower then the mercury goes down the tube.
Pascal (Pa)
SI unit of pressure.
standard atmosphere
the pressure required to support 760mm of mercury in a mercury barometer at 25 degrees C.
Vaporization
the change from a liquid to a gas or vapor. occurs quickly.
evaporization
occurs at the suface when it is not boiling
Vapor pressure
a messure of the force excerted by a gas abovee a liquid.
boiling point
the temp. at which the vapor pressure of the liquid is just equal to the external pressure on the liquid
melting point
the point at where a solid becomes a liquid.
unit cells
the smalles group of particals within a crystal that remains the geometric shape of the crystal.
allotropes
two or more different mollecular forms of the same element in the same physical shape.
amorphous solid
lacks an ordered internal structure
sublimation
solid to a vapor without changing into a liquid
triple point
the only set of conditions at which all three phases can excist in equilibrium together.