The Ideal Gas Equation - R Units Value L atm/mol K 0.08206...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
The Ideal Gas Equation The three historically important gas laws derived relationships between two physical properties of a gas, while keeping other properties constant: These different relationships can be combined into a single relationship to make a more general gas law: If the proportionality constant is called "R", then we have: Rearranging to a more familiar form: This equation is known as the ideal-gas equation An "ideal gas" is one whose physical behavior is accurately described by the ideal-gas equation The constant R is called the gas constant o The value and units of R depend on the units used in determining P , V , n and T o Temperature, T , must always be expressed on an absolute-temperature scale ( K ) o The quantity of gas, n , is normally expressed in moles o The units chosen for pressure and volume are typically atmospheres ( atm ) and liters ( l ), however, other units may be chosen o PV can have the units of energy:
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Therefore, R can include energy units such as Joules or calories Values for the gas constant
Background image of page 2
Background image of page 3
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: R Units Value L atm/mol K 0.08206 cal/mol K 1.987 J/mol K 8.314 m 3 Pa/mol K 8.314 L torr/mol K 62.36 Example: If we had 1.0 mol of gas at 1.0 atm of pressure at 0C (273.15 K), what would be the volume? PV = nRT V = nRT/P V = (1.0 mol)(0.0821 L atm/mol K)(273 K)/(1.0 atm) V = 22.41 L 0 C and 1 atm pressure are referred to as the standard temperature and pressure (STP) The molar volume of an ideal gas (any ideal gas) is 22.4 liters at STP Example: Nitrate salts (NO 3-) when heated can produce nitrites (NO 2-) plus oxygen (O 2 ). A sample of potassium nitrate is heated and the O 2 gas produced is collected in a 750 ml flask. The pressure of the gas in the flask is 2.8 atmospheres and the temperature is recorded to be 53.6 C. How many moles of O 2 gas were produced? PV = nRT n = PV/RT n = (2.8 atm * 0.75 L) / (0.0821 L atm/mol K * (53.6 + 273)K n = (2.1 atm L) / (26.81 L atm/mol) n = 0.078 mol O 2 were produced...
View Full Document

Page1 / 3

The Ideal Gas Equation - R Units Value L atm/mol K 0.08206...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online