Chemistry Chapter 14.3 “Ideal Gases”

I. Ideal Gas Law A. Review… 1. Combined Gas Law – uses 3 variables *assume that ________ does not change. B. New Variables… 1. n = number of moles of gas 2. R = ideal gas constant -how did we get it? R = (P x V) / (T x n) (101.3 kPa x 22.4 L) / (273 K x 1 mol) = ? R = 8.31 C. New Equation… P x V = n x R x T Moles of gas

Practice Problems… 1. A deep underground cavern contains 2.24 x 106 L of methane gas (CH4) at a pressure of 1.50 x 103 kPa and a temperature of 315 K. How many moles is this? How many kilograms of CH4 does the caver contain? 2. When the temperature of a rigid hollow sphere containg 685 L of helium gas is held at 621 K, the pressure of the gas is 1.89 x 103 kPa. How many moles of helium does the sphere contain? How many helium atoms is this?

II. Ideal vs. Real Gases Ideal Gases Real Gases Follow gas laws of temperature and volume Do have volume and attraction between particles Conform to kinetic theory of matter Gases can turn into liquids and solids No volume or attraction to particles within the gas Differences occur at low temps and high pressures Examples…No gases meet these rules all the time Look at pg. 429 “Ideal vs. Real Gases” But… Ex: Anything that is a gas or can become a gas