5.1 First Law of Thermodynamics and Enthalpy | General Chemistry

Chad introduces the topic of energy and its units, comprehensively covers the First Law of Thermodynamics, and introduces Enthalpy. First, a basic definition of energy is provided and the Joules, calories, and nutritional Calories are introduced. The First Law of Thermodynamics is then covered both qualitatively and quantitatively as described by the equation:
DE = q + w
Calculations involving the flow of energy between system and surroundings through heat and work are explored.
Enthalpy is then introduced with a basic definition along with the definitions of Endothermic and Exothermic as types of reactions. An application of enthalpy to stoichiometry (thermochemical stoichiometry) then follows, and the lesson is concluded by describing/defining the six fundamental phase changes and the enthalpy associated with each.
I've embedded this playlist as a course on my website with all the lessons organized by chapter in a collapsible menu and much of the content from the study guide included on the page. Check this lesson out at www.chadsprep.com/chads-gener...
If you want all my study guides, quizzes, final exam reviews, and practice exams, check out my General Chemistry Master Course (free trial available) at www.chadsprep.com/genchem-you...
00:00 Lesson Introduction
01:04 Energy, Joules, and Calories
02:48 First Law of Thermodynamics
11:23 Enthalpy
19:26 Enthalpy Stoichiometry
23:29 Enthalpy and Phase Changes
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Пікірлер: 32

  • @verano.violet
    @verano.violet Жыл бұрын

    In just 10 minutes, You have explained to me what 3 different chemistry lecturers have failed to help me understand. Thank you so much.

  • @ChadsPrep

    @ChadsPrep

    Жыл бұрын

    You're welcome - Glad you got the help you needed!

  • @michailtimanov1841
    @michailtimanov184114 күн бұрын

    Sound and clean explanations! Nice, Chad!

  • @ChadsPrep

    @ChadsPrep

    14 күн бұрын

    Glad you liked it!

  • @genebelcherskeyboard
    @genebelcherskeyboard4 ай бұрын

    god bless you mr clean

  • @ChadsPrep

    @ChadsPrep

    4 ай бұрын

    HA! I don't remember the last time I saw that character in an ad.

  • @BOB_VOX
    @BOB_VOX3 ай бұрын

    Mr. chads, i have a question about enthalpy, so what is it basically and why is it related to q at constant pressure

  • @veselinavolik3002
    @veselinavolik300225 күн бұрын

    Hi hi!! thanks so much, these videos are so so amazing!! would u be able to make a video on steady state approximation for rate laws? that would literally be the best thing in the worldddd

  • @ChadsPrep

    @ChadsPrep

    25 күн бұрын

    I don't have it on youtube, but you can watch a video here where I derive the Michaelis-Menten equation for enzyme kinetics which has the steady state approximation as its foundation. www.chadsprep.com/chads-elementary-biochemistry-videos/4-2a-derivation-of-the-michaelis-menten-equation/ Hope this helps!

  • @timothywheeler671
    @timothywheeler671 Жыл бұрын

    the state function concept could simplify the conservation of energy -> I spent so much time in Physics trying to reason conservative and nonconservative forces (energy that leaves the system)

  • @ChadsPrep

    @ChadsPrep

    Жыл бұрын

    Hey Timothy! Hope the video helped :)

  • @justahugenerd1278
    @justahugenerd12787 ай бұрын

    24:39 got a good laugh out of me haha

  • @ChadsPrep

    @ChadsPrep

    7 ай бұрын

  • @Allisons-analysis

    @Allisons-analysis

    3 ай бұрын

    same. A much needed one 😂

  • @francinebissereth5682
    @francinebissereth56822 жыл бұрын

    20:50 don't we need to find out the mole, how did you know there was only one o2

  • @Uriakatos

    @Uriakatos

    Жыл бұрын

    the stoichiometric coefficient of the reaction. Essentially, that conversion factor of -572 kJ/1 mol O2 is another way of writing -572 kJ of energy per mole of O2. In other OTHER words, it is saying "there are 572 kJ of energy produced for each mole of Oxygen that is consumed." This is simply a true statement based on the chemical reaction and is not subject to how many moles of Oxygen are actually present.

  • @alexsheremett3097
    @alexsheremett3097 Жыл бұрын

    May I ask you a little question to tell you the truth I didn't understand the real concept at 20: 30 when we were looking for enthalpy change for 3 moles of O2 you said that you can't just multiply Δ H by 3 ... and to get the right result that's what exactly we (you) did Thank you in advance

  • @dj69321

    @dj69321

    10 ай бұрын

    He said you could actually, but then went on to demonstrate the math, which isn't necessary for this problem but is helpful to understand for more complex scenarios

  • @alexsheremett3097

    @alexsheremett3097

    10 ай бұрын

    @@dj69321 thanks🙏.... You know it's amazing I studied long time ago chemistry... In French!... For several decades now I didn't understand the core concept of acid base balance and general chemistry in general... Thanks to this guy and after 65 of his lectures I can say now that everything became more clear... At the beginning I started to review some French books but to my big surprise nothing has changed in their program... Stil everything is understandable... Thanks one more time for the feedback

  • @estimatingonediscoveringthree
    @estimatingonediscoveringthree2 жыл бұрын

    Is dna subject to entropy

  • @ChadsPrep

    @ChadsPrep

    2 жыл бұрын

    Perhaps you mean "Is the existence of DNA a violation of the 2nd Law of Thermodynamics?" A little bit of a loaded question, but if you looked at a piece of DNA inside one of your cells let's say, then it's production would in no way be a violation of the 2nd Law of Thermodynamics. However, if you want to ask about not whether a particular existing piece of DNA exists but perhaps how the 1st piece of DNA came into existence or something along those lines, it is not so clear cut. A dogmatic naturalist might say that there is no violation where as a dogmatic theist might claim that there is a violation. I might be willing to say at the very least that the origination of something as complex as DNA is surprising in light of the 2nd Law of Thermodynamics. That's my diplomatic answer :)

  • @estimatingonediscoveringthree

    @estimatingonediscoveringthree

    2 жыл бұрын

    @@ChadsPrep should we expect unmaintained dna to degrade to non-function, like in a virus

  • @estimatingonediscoveringthree

    @estimatingonediscoveringthree

    2 жыл бұрын

    Thank you!

  • @estimatingonediscoveringthree

    @estimatingonediscoveringthree

    2 жыл бұрын

    @@ChadsPrep appreciate all your hard work!!!!

  • @ChadsPrep

    @ChadsPrep

    2 жыл бұрын

    Perhaps, but that word 'unmaintained' is a little vague. But there are exonucleases and endonucleases that are fairly prevalent that will commonly 'degrade' DNA. But many of these don't require ATP which means they're carrying out processes that are spontaneous and are just speeding them up. So perhaps we might expect DNA to degrade to individual nucleotides or even further over time even without the aid of exo- and endonucleases.

  • @timothywheeler671
    @timothywheeler671 Жыл бұрын

    s.o to AZ 🇺🇲

  • @FrontierThesisYU
    @FrontierThesisYU6 ай бұрын

    I know they're equivalent and that it just depends on convention, but why would my Physics textbook and my MCAT prep books use the equation: "deltaU = Q - W", in which case the work done ON the system is NEGATIVE? Meaning, why use a minus instead of a plus? Seems far less intuitive than the way you teach it.

  • @ChadsPrep

    @ChadsPrep

    6 ай бұрын

    Just to be clear we are talking about ΔE = q + w?

  • @ChadsPrep

    @ChadsPrep

    6 ай бұрын

    ΔE and ΔU are used interchangeably and both equations are correct... but we have to be clear on what W is: when you see +W we are assuming that work is being done *on* the system (and so adds to the internal energy), when you see -W we are assuming work is being done *by* the system (and so is subtracted from the internal energy). A lot of text books use ΔU = Q - W, but check what the definition of work is in that case. My advice as always is to follow the equation used by your Professor!

  • @FrontierThesisYU

    @FrontierThesisYU

    6 ай бұрын

    Thank you! Do you have. Also, do you have videos on isothermal, isobaric, adiabatic, etc. processes, please? @@ChadsPrep

  • @ChadsPrep

    @ChadsPrep

    6 ай бұрын

    @@FrontierThesisYU In my physics playlist: www.chadsprep.com/chads-general-physics-videos/first-law-of-thermodynamics/

  • @FrontierThesisYU

    @FrontierThesisYU

    6 ай бұрын

    Thank you!!! @@ChadsPrep