The Bag Stays Sealed. Why Puff Up? Ideal Gas Laws

Why does a sealed bag of chips puff up on a mountain? We trap some gas in one glass cylinder with a sliding piston, a pressure gauge and a thermometer, and go step by step: a little history (Robert Boyle's J-tube in 1662, then Jacques Charles and Joseph Gay-Lussac), pressure as particles hitting the walls, why temperature must be in kelvin (T = t + 273), Boyle's law (P₁V₁ = P₂V₂ at constant temperature), Charles's law (V₁/T₁ = V₂/T₂ at constant pressure), Gay-Lussac's law (P₁/T₁ = P₂/T₂ at constant volume), the combined gas law (P₁V₁/T₁ = P₂V₂/T₂) and the ideal gas law PV = nRT (R = 8.314 J/(mol·K) = 0.082 L·atm/(mol·K), 22.4 L per mole at STP). Plus two typical high-school exam problems solved step by step: a combined gas law problem and finding the number of moles with PV = nRT. 0:00 Why does a chip bag puff up? 0:29 Boyle, Charles and Gay-Lussac 0:56 Pressure, volume, temperature (kelvin!) 1:27 Boyle's law: P₁V₁ = P₂V₂ 1:54 Charles's law: V/T constant 2:19 Gay-Lussac's law: P/T constant 2:45 The combined gas law 3:03 Ideal gas law: PV = nRT 3:35 Exam problem 1: combined gas law 4:18 Exam problem 2: moles from PV = nRT 4:52 Recap 5:20 Next: thermodynamics More from the series: Newton's First Law:    • Newton's First Law Explained Simply (ΣF = ...   Newton's Second Law:    • Newton's Second Law Explained Simply (ΣF =...   #physics #chemistry #gaslaws