Ch 5 gases

# Ch 5 gases - Ch. 5 Gases A. Properties: a. No fixed volume...

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Ch. 5 Gases A. Properties: a. No fixed volume b. No fixed shape (take shape of container) c. Highly compressible d. Mix or react completely w/ other gases e. Exert pressure on their surroundings f. very low densities B. 5.2 Pressure: result of molecular collisions a. Pressure = a.i. factors: a.i.1. fewer gas particles, lower pressure a.i.2. decreases with altitude b. 1 Pa = N/m 2 ; but we will only use torr or ( mm Hg ) + stand atmosphere ( atm ) c. 1 atm = 760 torr = 760 mm Hg = 101,325 Pa = 14.7 psi c.i. Tire pressure: 2.18 atm, 1650 torr c.ii. Blood pressure: .16/.11 atm, 120/80 torr d. measured with a b arometer : evacuated glass tube, tip of which is submerged in mercury; d.i. The barometer was created in 1643 by Torricelli, who inverted a tube filled w/ mercury into a dish d.ii. At sea level, column of mercury is 760 mm tall d.iii. Atm pressure is used to predict weather; low pressure often indicate a storm nearing e. Manometer e.i. U-shaped tube containing dense liquid e.ii. Measure gas pressure inside a flask relative to atm pressure e.iii. diff in height = diff of pressure of gas relative to atm C. 5.3 Simple Gas Laws a. Boyle’s law: PV = k (pressure + volume inversely proportional) a.i. Pressure + Volume a.ii. At constant temperature, the pressure + volume of a gas are inversely proportional a.ii.1. PV= k, or P 1 V 1 = P 2 V 2 a.ii.2. Why? Because gas particles collide with the container more. Don’t always follow ideal gas law completely b/c they do collide with each other a lot too. a.ii.3. All pressure involving gases is due to gas particle colliding w/ container; as pressure of a gas increases, particles of gas collide more frequently with walls of container

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## This note was uploaded on 02/17/2012 for the course CHEM 105ALg taught by Professor Bau during the Spring '07 term at USC.

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Ch 5 gases - Ch. 5 Gases A. Properties: a. No fixed volume...

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