As a system increases in volume, it absorbs 52.5 J of energy in the form of heat from the surro

As a system increases in volume, it absorbs 52.5 J of...

Key Concepts

Unit Conversions Between atm·L and Joules

Thermodynamic calculations often require converting units so that work and energy are in compatible forms. Specifically, the conversion factor between pressure-volume work measured in atm·L and energy in Joules is crucial. This conversion ensures that calculated quantities like work done by the system or on the system match the units used in the overall energy balance.

Sign Conventions in Thermodynamics

Recognizing the sign conventions for heat and work is vital in thermodynamic analyses. Different conventions may be used for work and heat, such as considering work done by the system as negative or work done on the system as positive. Proper application of these conventions is essential when applying the First Law of Thermodynamics and in calculations involving internal energy, heat, and work.

First Law of Thermodynamics

This law states that the change in the internal energy (?U) of a system is equal to the heat added to the system (Q) plus the work done on the system (W). It is a statement of energy conservation specific to thermodynamic systems, linking internal energy, heat, and work, and is fundamental in analyzing energy exchanges during processes such as expansion or compression.

Pressure-Volume Work

This concept involves the work performed when a system changes its volume against an external pressure. When a gas expands or compresses, it does work against a constant pressure, calculated by the product of that pressure and the change in volume (?V). The work is often expressed with appropriate unit conversions, such as converting atm·L to Joules, which is essential for consistency in thermodynamic calculations.

Transcript

00:01 In this particular video, we're going to find the initial volume of a system based on the following information.

00:09 So we know the volume is increasing.

00:12 We know that he is being absorbed by the system.

00:15 At last 5 52.5 jewels, we have a pressure of 0.5 atmospheres.

00:23 We have a final volume of 58 leaders, and we have the overall change of energy in the system as negative 102.5.

00:33 So the main way to solve this particular problem is that we need to find the work done.

00:40 And once we have the work done, we can figure out what the initial volume is.

00:46 So i went ahead and wrote that at the bottom, that sort of our two step process here.

00:50 I mean, if i work done, and then we can find, uh, the initial volume, it's working.

00:56 He's actually both of these equations will use the one on the left first to find work, and then once we find work, will go ahead and find delta v or the part of delta v.

01:06 We need the initial volume.

01:08 So going in at a screen here.

01:12 Okay, so the 1st 1 we're gonna d'oh is we know delta is negative one on 2.5 jewels and we know we have heat transferred in at 52.5.

01:40 We just need mystery number w so if we subtract 52.5 from each side, we will have negative 150 modules worth, uh, work.

02:00 Now we need to convert that over to leader atmospheres because that is the working those air, the working units for work when it comes to pressure and volume.

02:11 So i do know that one atmos or one leader atmosphere carries one a 1.3 jewels worth of energy.

02:20 So i'll go ahead and convert that real quick...

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