Chem #8 Flashcards
gases and liquids are ____
fluids
sphygmomanometer
medical devices that measure blood pressure (mmHg)
Normal BP: 120 systolic and 90 diastolic
understand how a barometer works
Many medical devices use the same conceptual design of a barometer.
• Atmospheric pressure creates a downward force on the pool of mercury at the base of the barometer while the mercury in the column exerts an opposite force (its weight) based on its density.
• When the external air exerts a higher force than the weight of the mercury in the column, the column rises, and vice versa.
ideal gas
hypothetical gas with molecules that have no intermolecular forces and occupy no volume
ideal gas law
shows relationship between Pressure, Volume, moles, and temperature for an ideal gas.
o Used to analyze the relationships between variables when certain ones are held constant.
combined gas law
: changes in temperature, volume, and pressure of a gas
what are the requirements of an ideal gas?
no intermolecular forces and occupy no volume
real gas
: deviate from ideal behavior at high pressures (low volumes) and low temperatures because of intermolecular forces or volume effects.
when do real gases deviate from ideal behavior?
high pressure (low volume) and low temperature
the gas laws show that ____
that all gases show similar physical characteristics and behavior irrespective of their particular chemical identity.
the ideal gas constant for the ideal gas law can be rounded to ____
0.8
the ideal gas constant for the ideal gas law can be rounded to ____
0.08
how to solve for molar mass at STP given density
o Molar mass equals the density at STP x 22.4 L/mol
Holding mass constant for calculations using combined gas law.
avogadro’s principle
all gases at a constant temperature and pressure occupy volumes that are directly proportional to the number of moles of a gas present.
As the number of moles of gas increases, the volume increases in direct proportion.
boyle’s law
for a given gaseous sample held at constant temperature (isothermal conditions) and constant moles, the volume of the gas is inversely proportional to pressure.
As pressure increases, volume decreases.
charle’s law
at constant pressure, the volume of a gas is proportional to its absolute temperature, expressed in K. n and P are constant
As temperature increases, volume increases.
gay lussac’s law
at constant volume, the pressure of a gas is proportional to its absolute temperature in kelvins. n and V are constant
As temperature increases, pressure increases.
dalton’s law of partial pressures
o When two or more gases that do not chemically interact are found in one vessel, each gas will behave independently of the others.
Each gas will exert pressure independently of the other gases, as if it were the only gas present: partial pressure of the gas.
the total pressure of a gaseous mixture is equal to the sum of the partial pressures of the individual components.
Partial pressure of a gas is related to its mole fraction
partial pressure of a gas is related to its ____
mole fraction
henry’s law
The solubility of a gas will increase with increasing partial pressure of a gas.
vapor pressure
: the pressure exerted by evaporated particles above the surface of a liquid
Vapor pressure from the evaporated molecules forces some of the gas back into the liquid phase, and equilibrium is reached between evaporation and condensation.
what are the assumptions of the kinetic molecular theory
o 1. Gases are made up of particles with volumes that are negligible compared to the container volume.
o 2. Gas atoms or molecules exhibit no intermolecular attractions or repulsions.
o 3. Gas particles are in continuous, random motion, undergoing collisions with other particles and the container walls.
o 4. Collisions between any two gas particles (or between particles and the container walls) are elastic, meaning that there is conservation of both momentum and kinetic energy.
o 5. The average kinetic energy of gas particles is proportional to the absolute temperature of the gas (in kelvins), and it is the same for all gases at a given temperature, irrespective of chemical identity or atomic mass.
kinetic molecular theory
explain the behavior of gases.
The higher the temperature, the ____ molecules move. The larger the molecules, the ____ they move.
faster
slower
