Intro to Gas Laws Flashcards
(22 cards)
gases exert ________ by ____________.
pressure; collisions
gases are mainly ________ space.
empty
what are the four main gas variables?
pressure (P), volume (V), temperature (T), number of moles (n)
what is pressure?
the force exerted per unit of surface area (force/area)
what is the SI unit for pressure
pascal (Pa)
what units are expressed in pressure?
inches of mercury (in Hg)
centimeters of mercury (cm Hg)
millimeters of mercury (mm Hg)/torr
what does psi stand for?
pounds per square inch
what is the reference pressure? what is it? what can it be expressed in?
standard pressure. the normal pressure of the atmosphere at sea level on a fair weather day. p, v, t, n, atm.
what are gases composed of?
tiny particles called molecules
what are the standard pressure values?
1.00 atmosphere (atm)
760 torr
14.7 psi
what is temperature?
a measure of the average kinetic energy and is measured in units called degrees
where does the Kelvin scale start?
at absolute zero, the coldest temperature possible, where there is no motion of the gas molecules
memorize this:
there are no negative values in Kelvin, it cannot be colder than 0 K
K = ? degreeC = ?
K = degreeC + 273 degreeC = K - 273
what is the reference temperature? what is it?
standard temperature. the value is the normal freezing point of water at standard pressure
what are the standard temperature values ?
0 degreeC, 273 K, 32degreesF
what is STP?
standard temperature and standard pressure
what values can be used for STP
0degreeC 273 K 1.00 atm 760 torr 14.7 psi
what is Boyle’s Law? what is the equation at constant temperature ?
when the pressure gets bigger the volume gets smaller and vice versa as long as you keep the same temperature and the same number of molecules
V1 = P2
— — or P1V1 = P2V2
V2 P1
what is Charles law? what is the equation ?
the relationship of temperature and volume for a sample of gas at constant pressure. when the temperature increases, so does the volume and vise versa as long as you keep the temperature the same.
V1 = V2
— —-
T1 T2
memorize this:
when we work with gas law problems that involve a temperature change we must work with the Kelvin temperature scale
if you double the Kelvin temperature, what happens to the volume? triple?
volume doubles; volume triples
