# Chapter 10: Gases So far weve seen constant V 1/P (Boyles law) V T (Charless law) P T (Gay-Lussacs law) V n (Avogadros law) PV =R nT (same ratio for every gas) ideal gas constant: R = 0.08206 Latm/molK Ideal Gas Law

PV = nRT NO Units of : mL , mmHg , kPa , grams , C Ideal Gas Law Calculations o 1. A 5.00 L balloon is at 0.855 atm and 25 C. How many moles of gas are in the balloon? PV = nRT R = 0.08206 (0.855 atm)(5.00 L) = n (0.08206)(298 K) (0.855)(5.00) = n (0.08206)(298)

n = 0.175 mol Ideal Gas Law Calculations 2. What is the pressure of 0.435 mol He gas in a volume of 8.12 L at 0.00oC? PV = nRT R = 0.08206 P (8.12 L) = (0.435mol )(0.08206)(273 K) P = (0.435)(0.08206)(273) (8.12) P = 1.20 atm Ideal Gas Law Calculations 3. A sample of aluminum chloride gas weighing 0.0500 g at 350.oC and 760 mmHg of pressure occupies a volume of 19.2 mL.

Calculate the Molar Mass of the gas. PV = nRT R = 0.08206 (1.00 atm)(0.0192 L) = n (0.08206)(623 K) n = 0.000376 mol __0.0500 g_ Molar = grams M= 0.000376 mol Mass mole AlCl3 = 133 g/mol