Chemistry Chapter 10
Terms
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- kinetic energy
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kenetic = motion
the energy an object has because of its motion - kinetic theory
-
tiny particles are in constant motion
1. a gas is composed of particles
2. the particles move rapidly in constant motion
3. all collisions are perfectly elastic - gas pressure
- the force exerted by a gas per unit surface area of an object
- vacuum
- an empty space with no particles and no pressure
- atmospheric pressure
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results from collisions of air molecules with objects
*decreases as you climb a mountain because the air layer around the Earth thins out as elevation increases - barometers
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devices commonly used to measure atmospheric pressure
dependent on weather - pascal (Pa)
- the SI unit of pressure
- standard atmosphere (atm)
- the pressure required to support 760 mm of mercury in a mercury barometer at 25 deg C
- 1 atm =
- 760 mm Hg
- 1 atm = 760 mm =
- 101.3 kPa
- vaporization
- conversion of a liquid to a gas or vapor
- evaporation
- the process when vaporization occurs at the surface of a liquid that is not boiling
- vapor pressure
- a force due to the gas above the liquid
- boiling point (bp)
- the temperature at which the vapor pressure of the liquid is just equal to the external pressure
- normal melting point
- the boiling point of a liquid at prssure of 101.3 kPa
- melting point
- the temperature at which a solid turns into a liquid
- crystal
- the atoms, ions, or molecules that make p te solid substance are arranged in an orderly, repeating, 3D pattern
- unit cell
- the smallest group of particles within a crystal that retains the geometric shape of the crystal
- simple cubic unit cell
- atoms or ions are arranged at the corners of an imaginary cube
- body-centered cube unit cell
- the atoms or ions are at the corners and in the center of an imaginary cube
- face-centered cube unit cell
- the atoms or ions are in the center of each face of the imaginary cube (no atom/ion at the center)
- allotropes
- two or more different molecular forms of the same element in the same physical state
- amorphous solids
- lack an ordered internal structure
- glasses
- transparent fusion products of inorganic substances that have cooled to a rigid state without crystallizing
- phase diagram
- gives the conditions of temperature and pressure at which a substance exists as solid, liquid, and gas (vapor).
- triple point
- describes the only set of conditions at which all three phases can exist in equilibrium with one another
- sublimation
- the change of a substance from a solid to a vapor without passing through the liquid state