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Apologia Chemistry Module 12
Terms in this set (37)
the force per unit area exerted on an object
explain gas pressure
gas molecules move quickly-thus they bump into stuff -this stuff is struck with the molecules exerting force. the average force per unit area that these collisions exert one the object is called the gas pressure
What is a Pressure unit measured in terms of?
Newtons / meters²
What is the pressure unit of N/m² re-named to?
Pascal (after Blaise Pascal). Abbreviated: Pa
What are the four units chemists use to measure pressure?
Pa (Pascal), atm (atmosphere), torr, and mmHg (millimeters of mercury (Hg))
Atmospheric pressure is mostly constant, so we can use this value as an alternative unit to measure pressure
1.000 atm = 101.3 kPa (kilo Pascal)
mmHg stand for?
millimeters of mercury
Two other alternative units for pressure 1.000 atm are:
1.000 atm = 760.0 torr
1.000 atm = 760.0 millimeters of mercury, or mmHg
what is the PV relationship called?
Boyle's law is PV = constant
- what does this mean?
As long as the temperature of the gas stays the same throughout the experiment the product of gas' volume and its pressure is always the same
If Pressure increases Volume ___________ and if Volume decreases Pressure ______?
decreases ------ Increases
the pressure of an ideal gas does not depend on the _____ of the gas. it depends only on the _____ of that gas.
(1st blank) Identity (2nd blank) quantity
Define: Boiling point
Boling point: the temperature at which the vapor pressure of a liquid is equal to normal atmospheric pressure.
Define: Vapor Pressure
vapor pressure: the pressure exerted by the vapor with sits on top of any liquid.
Explain: Boiling point
explain: vapor pressure of water equals 100 C which equals boiling point which equals 760.0 torr which also equals 1.000atm
Vapor pressure of any liquid increases with _____?
Define: Mole Fraction
mole fraction: is used in the context of a mixture...it is a concentration unit ----- Mathematically the mole fraction of any component in a mixture.
give the mole fraction equation
X = number of moles of component / total number of moles in the mixture
If the gas temp raises and the pressure is constant then the volume does what?
Define Charles's law
Charles's law: at constant pressure the temperature and volume of a gas are lineary proportionall V/T = constant
How does Charles' law relate to the Kinetic theory of matter.
increase the temp, the molecules will move faster, the pressure is set, so they spread out as to not hit things as much...this would raise the pressure if they did.
following an eslablished trend in the data even though there is no data available for that region.
give Boyle's and Charles's Laws combined in the new mathematical equation
P1 V1/ T1 = P2 V2 / T2
Write the ideal gas law
What does "R" refer to in the ideal gas law?
"R" refers to a special physical constant
give the value of "R"
"R" = 0.0821 L x atm/ mole x K
state: Dalton's law of partial pressure
when 2 or more ideal gases are mixed together the total pressure of the mixture is equal to the sum of the pressure of each individual gas.
Give "Dalton's law of partial pressure" equation
Pt = P1t + P2 + P3 etc ------------------------------------Pt = total pressure----------------------------------------------P1 etc = pressure due to each gas = partial pressures
GIVE THE 3 PROPERTIES OF AN IDEAL GAS!
(1) The molecules (or atoms) that make up the gas are very small compared to the total volume available to the gas - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - (2) The molecules (or atoms) that make up the gas must be so far apart from each other that there is no attraction or repulsion between them - - - - - - - - - - - - - - - - - - - - (3) The collision that occurs between the gas molecules (or atoms) must be elastic
Explain rule number three of the ideal gas properties
when The molecules (or atoms) that make up the gas collide no energy can be lost in the collision. also, no energy can be lost when the molecules of the gas collide with the walls of the container.
explain why gases tend to behave ideally at high temps and low pressures?
molecules must be small compared to the total volume of the gas, and must be far apart. Thus the larger total volume that the gas occupies the more ideal it is Boyle's law (gas occupy large volumes at low pressures) and Charles law (gases occupy larger volumes at high temps) combined!
state the Kinetic theory of matter
molecules (or atoms) that make up a substance are in constant motion.
What is STP?
A temp of 273 K and a pressure of 1.00atm
a gas with a temp that is close to (or lager than) 273K and a pressure that is near (or lower than) 1.00atm will behave ideally
If the volume of a gas is zero, temp is what?
you can't cool something lower than what?
Absolute temperature scale is what?
Kelvin's temperature is -Absolute temp scale. because you can never reach 0.00K because you can never reach -273.15 C