chapter 7; Changes of State and the gas Laws Flashcards
kinetic molecular view
describes behavior of gases at the molecular level
gaseous atoms and molecules are in constant motion, moving at […] speeds
high
greater speeds =
greater kinetic energy
gaseous atoms or molecules move in […] lines in […] directions, […] with walls of their container, and fill entire container
straight
random
collide
greater speeds = greater kinetic energy =
higher temperatures
gaseous atoms or molecules are […] apart from one another and have […] intermolecular forces of attraction
far
negligible
gases are […] giving them unique properties that are different from […] and […]
compressible
gases
liquids
gas particles collide with the walls of the container, creating […]
pressure
Pressure (P) =
force / area
1 atmosphere (atm) =
760 millimeters of mercury (mmHg) used in medicine
760 torr
14.70 pounds per square inch (psi) English unit for pressure
101,325 pascals (Pa)
at sea level, atmospheric pressure is how many atm
1 atm
higher altitudes =
Lower atmospheric pressure
- fewer molecules pressing down
- less oxygen per breath
why do people who climb mount Everest usually carry cylinders of oxygen with them
the decreased atmospheric pressure at high altitude means that less oxygen is inhaled with every breath. Cylinders of oxygen provide supplemental oxygen and at a higher pressure
what are the four variables that describe the macroscopic properties of a gas
pressure (P)
volume (V)
temperature (T) and
moles (n)
what is the pressure volume relationship (Boyle’s law)
pressure and volume are inversely proportional when n and T are constant
what is the volume temperature relationship (Charles’s law)
volume and temperature are directly proportional when n and P are constant
what is the pressure temperature relationship (Gay Lussac’s law)
pressure and temperature are directly proportional when n and V are constant, and T is given in kelvins
in a graph how is the Boyle’s law shown
(constant temperature)
- as volume increases pressure decreases
pressure vs 1/V
if inversely it is straight line with pressure increasing as 1/V
in a graph how is Charles’s law shown
(constant pressure)
- increase temperature so does the volume
proportional
in a graph how is Gay-Lussac’s law
(constant volume)
- as temperature increases there is increase in pressure
what is the equation of Boyle’s law
PiVi = PfVf
what is the equation of Charles’s Law
Vi/Ti = Vf/Tf
volume and temperature are directly proportional
tmp is given in kelvins
convert celcius to kelvin
kelvin = celcius + 273
what is the equation of gay-lussac’s law
Pi/Ti = Pf/Tf
pressure and temperature are directly proportional
T is in kelvins
what is the combined gas law: pressure, volume, and temperature
PiVi/Ti = PfVf/Tf
when is the combined gas law used
when there is a fixed amount of gas, n, and the variables P, V, and T are changing
what is the volume mole relationship (Avogadro’s law)
moles of gas, n, is directly proportional to volume, V, of the gas (constant T and P)
what is the equation of the volume-mole relationship (avogrado’s law) equation
Vi/ni= Vf/nf
constant pressure and temperature
what is standard temperature and pressure (STP)
0 degrees Celsius
(273.15 K)
and 1 atm of pressure
what is molar volume of a gas at STP
22.4 L
one mole of any gas at […] degrees celsius and […] atm occupies a volume of […] L, known as the molar volume of a gas
0
1
22.4
what is 1 mole = in L at STP
22.4L
1 mole = 22.4 L
what is the density of a gas at STP equation
density = molar mass / molar volume (22.4 L/mol)
example of density of helium
density (helium) = (4.00 g/mol) / (22.4 L/mol) = 0.179 g/L less dense then air
what is the molar mass of air
28.8 g/mol
if divided by STP
28.8 g/mol / 22.4 L/mol
= 1.29 g/L
when something is less dense than air does it float or sink
sink
how many gases do gas mixtures contain
two or more
what is daltons law of partial pressures
- each gas in a mixture exerts a pressure independent of other gases, behaving as if it alone occupied the total volume
- Dalton’s law states that the total pressure of a gas mixture is equal to the sum of the partial pressure of each gas in the mixture
what Daltons Law of partial pressure equation
Ptotal = P1 +P2 + P3 + … Pn
P1, P2, P3 …, Pn are partial pressures of the gases in the mixture
what is the percentage oxygen in the atmosphere
20.95%
e.g.
at sea level (760 mmHg), the partial pressure of oxygen is)
+
on Mount Everest (400 mmHg) the partial pressure of oxygen
0.2096 x 760 mmHg = 159 mmHg
0.2096 is 20.95% of oxygen in the atmosphere divided by 100
+
0.2095 x 400 mmHg) the partial pressure of oxygen is 84 mmHg
what does Henry’s law state
that the number of moles of gas, n, dissolved in a liquid is directly proportional to the partial pressure, P, of the gas
what dissolved gases does blood serum contain
oxygen nitrogen, and carbon dioxide
what is Henry laws equation
P = K subscript H C P=KHC (t is constant)
what do the letters stand for in Henrys Law equation P = K subscript H C
P = the partial pressure of the gas
K subscript H = Henry’s constant which is unique for each gas
C = the concentration of the dissolved gas (mol/L)
how to solve for concentration of the dissolved gas from Henry’s law P = K subscript H C
P/K subscript H = C
Henry’s law shows that the moles of gas dissolved in solution are […] to the partial […] of the gas
proportional
pressure
Is volume and temperature proportional
Yes, as temperature increases volume.
