ideal gas law final
TRANSCRIPT
• Alteration of combined gas law– IGL calculates the number of
moles of a gas in a fixed volume at a known temperature and pressure
– Relates Moles, Pressure, Volume, & Temperature
• Describes the behavior of an “ideal” gas
• Cannot be used when a gas
is at its critical points
(Extreme Temperatures & Pressures or Phase Changes)
• Gases in the real world
• A gas that cannot be explained or described by the Ideal Gas Law
• Take into account:– Compressibility– Specific heat capacity– Van der Waals forces
• Defined in an environment in which all collisions between molecules or atoms are perfectly elastic (no intermolecular forces)
• There is no such thing as an “Ideal Gas”
• An ideal gas has no forces of attraction between molecules (IM forces)
• The molecules in the gas occupy “no volume”
Four Variables
• P = pressure (must be converted to kPa or atm)
• V = volume (must be converted to Liters)
• T = temperature (must always be in K)
• n = moles
Universal Gas Constant
R = 0.0821 L atm/ K mole or
-Used to interrelate the variables of a gas
• Derived from Boyle’s, Charle’s and Avagadro’s law from the Ideal Gas Law
• Constant n & T = Boyle’s Law
• Constant n & P = Charles’s Law
• Constant P & T = Avogadro’s Law
• Constant n & V = Gay Lusac’s Law
• We can calculate the value of R from the other variables in the ideal gas equation.
• At STP (O degrees C or 273.15 K) and a pressure of 1 atm at the standard molar volume (22.414 L) We can solve for R
• R= 0.0821 L atm/ K mole
• Can be used to describe the behavior of real gases at pressures around or less than 1 atm and temperatures around room temperature
• Gases like this behave close enough to an ideal gas such that PV=nRT can adequately describe their behavior
A 1.50 mole sample of Helium is placed in a 15.0 L container at 400K. What is the pressure in the container?
Answer: 332 kPaUse C+273=K for calculations
• Evan has 23.7 grams of nitrogen gas in a 30.8 L container with a pressure of 1.5 atm. What is the temperature of the gas?
• Answer: 670 K
• Pratheek has 2.03 moles of Helium in a 400.1 mL container at 282 degrees Celsius. What is the pressure of this gas in kPa?
• Answer: 23400 kPa