<p>I haven't started much of Thermodynamics yet. It's the only section left for me. What topics should I focus on the most? The FR PV diagrams? Should I just memorize all of the equations and plug numbers in? Can someone just memorize the equations and "plug them in?" Is it really that easy or are there tricks to it. I've seen a lot of questions say work done ON the system and work done BY the system. Does that refer to the U=Q+W, W=-PV equations? Are the negative signs needed?</p>
<p>Basically, what should I study in Thermo given 2 days time?</p>
<p>I think some of the equations like PV=nRT are in the Chem AP because I'm using the review book too lol. I know there's a thermo section in Chem though.</p>
<p>Is there an easy way to remember all of the positive and negative signs of W=P(Delta)V?? I'm having a bit of trouble with it. I just need an easy way to remember it, preferrably a mneumonic device =] Thanks.</p>
<p>If you understand the concepts behind the negative/positive signs, you won't get confused by "which sign goes with which equation" sort of stuff. Just remember that when a system DOES work on its environment, the work is regarded as being negative (since energy is, in a way, leaving the system). Likewise, when the the system HAS work DONE on it, the work is regarded as being positive. So, when you look at P-V diagrams, try to find out what is going on in terms of volumetric and barometric change if you want to find the "sign" of work. Is volume/pressure increasing or decreasing? What does that signify in terms of work? Look over your physics book. Thermodynamics, in my opinion, is a lot more confusing than kinematics, but it's really basic once you understand it. </p>
<p>Also, be sure to look at last year's Physics B free response. One of the questions is a P-V diagram question. Ha, I don't think I did very well on it (but I still got a 5, so it just goes to show you that you don't need to stress over one particular topic even if you don't know it very well; just make sure you're solid on everything else).</p>
<p>From what I've seen on the multiple choice questions, most thermodynamic questions are pretty simple. The question would either ask you for the total energy of the system (i.e. if x work is done on the system, the system does y work, and z of heat is added to the system), or would ask you question regarding work/total energy, etc., given a PV graph.</p>
<p>Can someone explain this objective to me? Thanks in adv!</p>
<p>Explain qualitatively how the model explains the pressure of a gas in terms of collisions with the container walls, and explain how the model predicts that , for fixed volume, pressure must be proportional to temperature.</p>
<p>when molecules collide with the wall it creates impulse, which is caused by the force on the wall. the force applied over an area creates pressure</p>
<p>greater temperature means greater kinetic energy in the molecules which means greater speed which means greater impulse which means greater force which means greater pressure</p>
<p>Why ask? You obviously need to study it, so go study. You're just wasting time by asking an obvious question. You can study it in 48 hours if you really wanted to.</p>