properties of gases Flashcards
gases typically made from what types of elements?
nonmetals
T/F: gases typically have high molar masses and complex formulas
false: they have low molar masses and relatively simple formulas
behavior of gases in containers? are they compressible?
expand to fill containers
yes, they are highly compressible (since gases are mostly empty space)
describe density of gases?
very low. typically measured in grams per liter
the combination of 2+ gases always forms what type of mixture?
a HOMOGENOUS mixture
purpose of KMT?
describes behavior of gases under “ideal” conditions
how do gas particles move?
they have continuous and random motion. bounce off each other like billiard balls
gases are mostly ___ __. the volume of gas particles is thus assumed to be ___.
empty space
V gas particles assumed to be 0, negligible relative to total volume of container
do gas particles have IMFs as stated by the KMT?
no! attractive/repulsive forces between gas molecules are negligible
does the average kinetic energy of gas molecules change if temperature stays constant?
no
average kinetic energy is proportional to ___
absolute temperature
what 4 properties do we usually use to describe gases? typical associated units?
pressure (atm)
volume (L)
temperature (K)
amount of gas (moles)
define pressure
amount of force applied to a unit of area
units we can use for pressure?
atm (atmospheres)
Pascals (SI unit)
bar (10,000 Pa)
mmHg/torr
define atmospheric pressure
weight of air per unit of area
what is standard atmospheric pressure?
how do we express this in atm?
normal atmospheric pressure at sea level. 1.00 atm = 760 torr/mmHg = 101.325 kPa
what is standard temperature and pressure?
standard temp = 0 C or 273.15 K
standard pressure = 1 atm
what temp is room temp?
25 C
equation typically used for pressure?
P = force aka newtons/area (m^2)
conversion from C to K?
K = 273.15 + C
gas behavior conforms to ideal equations at ___ and ____. why?
high temperatures and low pressures
high temps prevent IMFs/gases move faster
low pressures keep molecules further apart
what is effusion? diffusion?
effusion = escape of gas molecules through tiny hole into an evacuated space
diffusion= spreading of gas molecules throughout space or a substance
how does molecular mass of gases and their speed relate to each other? what law expresses this relationship?
gases with lower masses are faster, while gases with higher masses are slower
BUT: average kinetic energy for any gas in a system IS THE SAME at any given temperature!
