LE 04 The Ideal Gas Law - LaBrake PDF

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The Ideal Gas Law Friday, September 2, 2016

What is it?

6:24 PM

• Allows us to predict behavior of gases • Combination of Boyle's, Charles', and Avogadro's Law • The equation is: PV = nRT • Pressure (P) in atm, volume (V) in L, Moles (n), universal gas constant (R) varies in units, and temperature (T) in K • Keeping certain variables constant can illustrate how individual gas laws act

The Universal Gas Constant (R)

• R depends on the rest of the units ○ IF volume(L), pressure(atm), temperature(K), and moles, THEN R = .08206 ○ IF volume(L), pressure(bar), temperature(K), and moles, THEN R = .08314 Ex: What is the value of the missing gas property? P = ? atm* V = 6.03 L P(6.03) = (.509)(.08206)(307) P = 2.13 atm n = .509 mol T = 34 = 307 K *since we are using atm, R = .08206 Ex: What is the value of the missing gas property? P = 800 torr = 1.05 atm* (1.05)(V) = (.023)(.08206)(353) V = ? mL V = .63 L = 630 mL n = .023 mol T = 80 = 353 K *since we are using atm, R = .08206

Standard Conditions

• Lab communities have decided on the following standards: ○ STP (Standard Temperature and Pressure): 0 and 1 atm  Used in class, older ○ SATP (Standard Ambient Temperature and Pressure): 25 and 1 bar  Newer, slow to catch on Ex: At STP, what is the volume in liters of 1 mol of a gas? P = 1 atm* V=?L (1)(V) = (1)(.08206)(273) n = 1 mol V = 22.4 L T = 0 = 273 K *since we are using atm, R = .08206

Number Density

• Defined as number of particles in a present volume, • You can rearrange the Ideal Gas Law equation to solve for

• This equation shows that two different gas samples (i.e. oxygen and nitrogen) can have the exact same number density if pressure and density are the same.

Molar Volume

• Defined as volume used per one mole of an ideal gas,

• Standard Molar Volume is molar volume of an ideal gas at STP, 22.4

at STP

) ) Mass Density ( ) Molar Mass ( Molar Volume ( ) Number Density/Molariy ( The ideal gas law combines all the gas laws and it adds in a gas constant (R) that changes based on the units used for the ideal gas law equation. You can make certain variables in the ideal gas law constant and the equation will act as a single gas law. There is also molar volume and number density. They are not related, but they are inverses of each...