chemistry chapter 11
Terms in this set (72)
energy that a body possesses by virtue of being in motion
molecules are always in motion
aimless path of gas molecules
collision where no energy is lost in contact
force exerted by a gas divided by area over which its exerted whenever it collides with an object
no gas particles exist
gas pressure of the atmosphere, decreases as altitude increases
tool to measure atmospheric pressure
SI unit of pressure
standard temp and pressure; temp: 273 K, pressure: 101.3 KPa
0 K when there is no energy coming from heat or light
conversion of a liquid to a gas
changing of a liquid to a gas; often under the influence of heat
forces holding molecular compounds together
force exerted by a gas released by a liquid in a closed container
state of balance between the liquid and gas
tool for measuring vapor pressure
point at which substance goes from liquid to gas
temp at which a substance changes to its gaseous state
melting point is the same as_____
orderly repeating 3D pattern, Any pure compound or element turns into this when frozen
the smallest component of a crystalline solid which has its unique crystal shape
different molecular forms of an element in the same physical state
do not have an ordered internal structure. give example
amorphous solid; glass
a change in a state of matter
phase change: melting, vaporization, freezing, condensation, sublimation
change from a solid to bass without going through a liquid phase
conversion of vapor or gas to a liquid
graph showing phases of a substance at specific pressures and temperatures
point where all three states are at the same point
boiling point at sea level, when atmospheric pressure is 1atm
normal boiling point
temp at which solid and liquid are at equilibrium at a total pressure of 1atm
normal melting point
the ability for particles to condense
follows all the gas laws perfectly and at all pressures and temperatures. obeys all assumptions of the kinetic molecular theory
gas that does not follow the ideal gas statements
the contribution each gas makes to the total pressure in a container with a mixture of gasses
movement of particles from areas of higher concentration to lower concentration
applies only to gasses: movement of gas through a pinhole,
what two things determine effusion
size (larger move slower) temp (heated move faster)
what are the kinetic molecular theory assumptions?
particles are small with insignificant volume and far apart with empty space between them, no attractive or repulsive forces between the molecules, move in straight line paths and random walk, all collisions are perfectly elastic
how does temperature of a gas raise when heat is added?
gas particle collide more often and the friction generates heat
what is the relationship between the kelvin temperature of a gas and its kinetic energy?
what is the main difference between a substance in it's gaseous sate and that same substance in its liquid state
the distance between the particles and how strong the forces are holding them together
what are the two ways in which a liquid can be vaporized
evaporation and boiling
what are the main differences between boiling and evaporation?
boiling takes place throughout the substance at a specific temp of 100 C and evaporation only takes place on top anywhere from 0-100 C
why is evaporation considered a cooling process?
substances take in and remove energy in order to evaporate
how can you change the boiling point of a liquid?
change the altitude. altitude increases boiling decreases
when a substance is boiling what is happening to its temp?
temp remains constant once it hits boiling point. the energy is being used to break IM forces instead of raising the temp
why are gases easily compressible?
there is empty space between the particles
what two things can cause gases to act non ideally?
attractive forces and volume
under what conditions do gases act the least ideally?
polar and large, high pressure and low temp
under what conditions do gases act most ideally?
small non polar, low pressure and high temp
how can ration PV/nRT be used to indicate the ideal nature of a gas?
if a gas is ideal, this ratio will be equal to one
pressure and volume are inversely proportional to one another, temp is constant P1V1=P2V2
volume and temp are directly proportional, pressure is constant V1/T1=V2/T2
Gay Lussac's Law
pressure and temp are directly proportional, volume is constant, P1/T1=P2/T2
combined gas law
ideal gas law
ideal gas constant
Dalton's law of partial pressure
Graham's law of effusion
rate of effusion is inverse proportional to the square root of the gas's molar mass; rate a/rate b= square root of molar mass b/ square root of molar mass a
how does atmospheric pressure change as altitude changes? why does this happen?
decreases as altitude increases. gravity is pulling the gas particles down, therefore there are less gas molecules the higher up you go
when is it possible for a molecule to have no kinetic energy?
O K when there is no energy coming from heat or light
how does perspiring cool you down when you exercise?
it removes energy from your body in order to vaporize the sweat. removing the energy lowers your body's temp
what is the connection between vapor pressure, atmospheric pressure and boiling point?
atmospheric pressure and vapor pressure have to equal each other in order for something to boil
why does ethanol have a higher vapor pressure than water? how does this affect boiling point?
it doesn't take much energy to become a gas so it boils faster because it boils when VP=atmospheric pressure and it's already high VP is close to the atmospheric pressure so it doesn't have that much higher to go. IM forces are weaker
describe the motions of particles in a solid state?
particles move in small vibrations
explain what happens on a molecular level as water moves from solid to liquid to gas
solid to liquid the molecules are still condensed but able to move around each other and liquid to gas space between the molecules increases greatly
why do ionic solids have higher melting points than molecular solids?
ionic solids have strong ionic bonds holding them together which are stronger than IM forces
what are the three allotropic forms of carbon?
graphite, diamond, bucky ball
conversion between atm and kpa
conversion between atm and mmHg
1atm= 760 mmHg
conversion between mmHg and KPa
760mmHg= 101.3 KPa