The gaseous state Flashcards
state the Boyle’s law
when temperature is constant, volume of a fixed mass of gas is inversely proportional to its pressure.
state the Charles’ Law
When pressure is constant, volume of a fixed mass of gas is directly proportional to its absolute temperature.
(directly proportional and graph passing through origin only when temperature is kelvin, if it is in celsius, it is proportional only.)
state Avogadro’s Law
When temperature and pressure is constant, the volume of a gas is directly proportional to the number of molecules present.
what is the ideal gas equation
pv=nrt
what are the SI units for the ideal gas equation
pressure = pa (pascal)
volume = m^3
temperature = kelvin
amount = mol
equation involving partial pressures
partial pressure = mole fraction (mole of that gas / total mole) x total pressure
what are the assumptions of ideal gas?
- the gas particles have negligible volume compared to the volume of the container
- the intermolecular forces of attraction between gas particles are negligible
- collisions between gas particles, and their collisions with the walls of the container, are perfectly elastic (no net loss or gain of kinetic energy during collision.
what are the conditions for real gases to behave ideally?
low pressure: gaseous molecules are relatively far apart, volume of the molecules is negligible compared to the volume of the container. intermolecular forces are also negligible as the particles are far apart.
high temperatures: gas particles have enough kinetic energy to overcome intermolecular forces, which can be considered insignificant.
how will gases deviate from ideal behavior
molecules with stronger intermolecular forces will show greater deviation.
for 1 mol of ideal gas, ratio pv/rt is equal to 1 at any pressure.
deviation is greatest at low temperatures and high pressures
why do gases deviate at high pressure
at high pressure, the volume of the container decreases. molecules are pushed closely together and can take up a significant portion of the container volume, resulting in less space in which the molecules can move. Thus, it is no longer valid to assume that its volume is negligible compared to the container volume, and so the gas deviates from ideal behavior.
why do gases deviate at low temperatures
as temperature is lowered, the kinetic energy of the gas particles decreases, causing them to move more slowly and intermolecular forces to become more significant. This also causes collisions to become inelastic. Eventually, it reaches a point where the particles can no longer overcome the intermolecular forces, at which point real gases liquefy when cooled to below its boiling point.
draw the boltzmann curve
y-axis = fraction of molecules
x-axis = molecular speed / kinetic energy
curve and starting from the origin
what is dalton’s law
total pressure = sum of partial pressures
define mole in terms of Avogadro’s constant
1 mole contains exactly 6.02 x 10^23 elementary entities
