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 the 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.

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

[verano.violet]

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

[raeesadhorat]

Hands down, you are theee most brilliant lecturer i have ever come across, Bless you and thank you so much

[michailtimanov]

Sound and clean explanations! Nice, Chad!

[munoss-u]

thank you, mr. superhero of general chem!

[BOB_VOX]

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

[timothywheeler]

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)

[francinebissereth]

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

[veselinavolik]

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

[yurimlee]

For "What's the enthalpy change when 9g H2O are produced in the reaction above?" problem, if H2O have 1 mole and enthalpy change equal to -286KJ, then can I directly multiply 0.5 mole H2O with -286KJ?

[FrontierThesisYU]

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.

[alexsheremett]

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