Chem: Chapters 13-14
Terms
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- Allotrope
- 2 or more different molecular forms of the same element in the same physical state
- Kinetic Energy
- the energy an object has because of its motion
- Kinetic Theory
- all matter consists of tiny particles that are in constant motion
- Gas Pressure
- results from the force exerted from a gas per unit surface area of an object
- Vacuum
- An empty space with no particle and no pressure
- Atmospheric pressure
- results from the collision of atoms and molecules in air with objects
- Barometer
- used to measure atmospheric pressure
- Pascal (Pa)
- The SI unit of pressure
- standard atmosphere (atm)
- 1 atm is the pressure required to support 760 mm Hg in a mercury barometer at 25 degree C
- Vaporization
- the conversion of a liquid to a gas or vapor
- Evaporation
- when such a conversion occurs at the surface of a liquid that is not boiling
- vapor pressure
- a measure of the force exerted by a gas above a liquid
- boiling point
- the temp at which the vapor pressure of the liquid is just equal to the external pressure on the liquid
- normal boiling point
- the boiling point of a liquid at a pressure of 101.3 Pa
- melting point
- the temperature at which a solid changes into a liquid
- crystal
- the particles are arranged in an orderly, repeating, 3D patern called a crystal lattice
- unit cell
- the smallest group of particles within a crystal that retains the geometric shape of the crystals
- amorphous solids
- lacks an orderly internal structure
- glass
- a transparent fusion product of inorganic substances that have cooled to a rigid state w/o crystallizing
- sublimation
- the change of a substance from a solid to a vapor without passing through the liquid stage
- phase diagram
- the relationships among the solid, liquid, or vapor states of a substance in a sealed container can be represented in a single graph
- the triple point
- describes the only set of conditions at which all 3 phases can exist in equilibrium with each other
- boyle's law
- states that for a given mass of gas at constant temperature the volume varies inadvertently with pressure
- Charles's law
- states that the volume of a fixed mass of gass is directly proportional to its kelvin temperature if the pressure is kept constant
- compressibility
- a measure of how much the volume of matter decreases under pressure
- Gay-Lussac's Law
- states that the pressure of a gas is directly proportional to the kelvin temperature if the volume remains constant
- combined gas laws
- describes the relationship among the pressure, temperature and volume of an enclosed gas
- Ideal gas constant (r)
- has a value of 8.31 (L X KPa)/ (K x mol)
- Ideal gas law
- PV=nRT
- partial pressure
- contribution each gas in a mixture makes to the total pressure
- Dalton's law of Partial Pressure
- at constant volume and temperature the totaly pressure exerted by a mixture of gases equals the sum of partial pressure of the component gases.
- diffusion
- the tendency of molecules to move towards and area of lower concentration until uniform.
- effusion
- when a gas escapes through a tiny hole in its container
- Graham's law of effusion
- states that the rate of effusion of a gas is adversely proportional to the square root of the gases molar mass