151F09Disc04D2L

151F09Disc04D2L - GenChem 4 th meeting Welcome to your Chem...

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GenChem 1 Welcome to your Welcome to your Chem 151 Chem 151 Discussion. Discussion. Where chemistry comes to you! Where chemistry comes to you! 4 th meeting
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GenChem 2 Today’s Agenda See how ideal gases behave Discover simple experimental relationships Form a group to work problems Participation exercise Try practice exam questions Assigned study practice
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GenChem From Observing From Observing experiments experiments 4 th week We find that Simple gases obey the ideal gas law PV=nRT Where P= pressure V= volume n= number of moles T= temperature R= a constant 0.082 L•Atmos/mol K)
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GenChem From your own experience and the equation PV=nRT Predict the changes below for A simple gas in a balloon. change V P R T ↑ ↑ increases ↓ decreases ─ no change P is directly proportional to T V is directly proportional to T Opposite sides of = sign
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GenChem From your own experience and The equation PV=nRT Predict the changes below for A simple gas in a balloon. change V T R P ↓ ↑ increases ↓ decreases ─ no change T is directly proportional to P V is inversely proportional to P Same side of = sign Opposite sides of = sign
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GenChem From your own experience and The equation PV=nRT Predict the changes below for A simple gas in a balloon. change V T R n ↑ ↑ increases ↓ decreases ─ no change Does adding More moles Make a balloon Colder? V is directly proportional to n T by the equation is inversely proportional to n No, sometimes equations can lead to incorrect conclusions. With a simple gas, changing n changes V and P but not T. Use good judgment
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GenChem Based on PV=nRT which graph is correct for the change in V as you increase T ? V T T V V T V T V T What’s wrong? “You increase T” makes T the INDEPENDENT variable which is placed on the X axis. And V is the DEPENDENT variable placed on the Y axis.
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GenChem Based on PV=nRT which graph is correct for the change in P as you increase V ? P V P V V P V P P V P vs V is inversely proportional As one increases the other decreases and PV = K or P 1 V 1 =P 2 V 2 WHAT’S WRONG? The graph is linear with a negative slope so P= -kV + b wrong graph!! This is a negative direct proportion
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GenChem So….Form a group of 4
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GenChem Osmotic pressure and dialysis
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GenChem The force needed to stop a material in a liquid from coming across a membrane is called the Osmotic Pressure ( π). This is very important in biological systems like your kidney and dialysis treatment. The experimental equation for Osmotic Pressure is π = C K T where π = pressure in atmos C = concentration of dissolved material in mol/L T = temperature (K) Based on this equation answer the following:
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GenChem The equation for Osmotic Pressure is π = C K T where π pressure in atmos C = concentration of dissolved material in mol/L T = temperature Based on the relationship answer the following: What is the type of relationship between π and T? A) Direct proportion
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This note was uploaded on 02/06/2012 for the course CHEM 151 taught by Professor Staff during the Fall '08 term at Arizona.

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151F09Disc04D2L - GenChem 4 th meeting Welcome to your Chem...

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