GAS LAWs Flashcards
Gases definition
Gases are compressible and expand to fill the available volume.
There are 3 variables in the Gas Law equations:
Pressure
Temperature
Volume
When one of these values is _______, the 3 gas laws
constant; predict the relationship between the other two.
Name 4 Laws
Boyle’s Law
Charles Law
Avogadro’s Law
Gay Lussac’s Law
Boyle’s Law (VP)
V1 * P1 = V2* P2
Charles’s Law
V1/ T1 = V2/T2
Avogadro’s Law
V1/n1 = V2/n2
Gay-Lussac’s Law
P1/T1 = P2/T2
Ideal Gas Law
PV = nRT
Combined Gas law
P1 x V1/T1 = P2x V2 / T2
The ideal gas law is most accurate for monatomic gases favored at
high temperatures and low pressures
A value for R is determined under a set of standard conditions called _____
standard temperature and pressure”, or
STP.
Standard temperature is defined as ___C or ____K
0c or 273K.
Standard pressure use to be 1 atm. Using atm/L/mol/K the value is calculated as 0.0821.
However, Standard pressure was changed recently to match SI Units and is now defined as_______
atm/L/mol/K ; 0.0821.
and is now defined as 100 kP
kPa/L/mol/K the value is calculated as
8.31.
The numeric value for R depends on which units are
being used to represent pressure in STP.
If atm, R =
If kPa, R =
- 0821 (old way)
8. 31 (new way)
At STP (_____ kPa, _____K) 1 mole of any gas takes up _____L.
(101.3 kPa, 273K) 1 mole of any gas takes up 22.7 L.
R is expressed in
L/mol/K
Defined Boyle’s Law
The Volume of a gas is inversely proportional to Pressure, if temperature and moles are constant
Boyle’s Law
Increasing pressure, volume ________. This is an ______relationship
We can see that by increasing the pressure on a gas, its volume decreases. This is an inverse, relationship. As one
variable goes up, the other goes down, and vice versa.
Applications of Gas Law
Ambubag being squeezed (increased pressure = decreased volume)
Pushing syringe against resistance (increased pressure = decreased volume)
Inspiration (negative pressure leads to increased volume)
Oxygen cylinder (gas being forced from a larger to smaller container results in
increased pressure in the cylinder
Define Charle’s Law
The Volume of a gas is directly proportional to Temperature (Kelvin), if pressure and moles are constant
For Charle’s Law, By increasing the temperature
he gas expands increasing
the volume. This is a direct relationship.
State Avogadro’s law
There is a ______relationship
As moles of gas increase, the volume increases, and vice versa, if pressure & temperature are constant.
direct
Avogadro’s law example
Using rigid container with movable piston.
Avogadro’s law
(Avogadro’s hypothesis) is one of the gas laws.
Equal volumes of gases, at the same temperature and pressure,
contain the same number of particles, or molecules.
The most important consequence of Avogadro’s law is the following:
The ideal gas constant has the same value for all gases.
One moles of an ideal gas occupies **22.7 liters (dm^3) **at STP (use to be 22.4 L but was changed by IUPAC). This volume is often referred to as the molar volume of an ideal gas. Real gases may deviate from
this value.
A mole is the STP unit of measurement for the amount of a
substance.
STP unit of measurement for the amount of a substance.
Mole =
given weight/molecular weight
The number of molecules in one mole is called Avogadro’s number =
approximately 6.022 ×1023 particles per mole.