You might even have a presentation you`d like to share with others. If so, simply download it from PowerShow.com. We will convert it into an HTML5 slideshow that includes all the types of media you have already added: audio, video, music, images, animations, and transition effects. Then you can share it with your target audience as well as millions of monthly visitors from PowerShow.com. And again, everything is free. 19 Heat output (specific heat)Specific heat at constant volume: Since internal energy is a state variable and does not depend on past states or how state changes occur, we can define internal energy changes as follows: If we replace our specific thermal equation with the first law: We can obtain an alternative form of the first law of thermodynamics: → Thermodynamics M. D. Eastin 18 Heat capacities (specific heats)Specific heat at constant volume: Starting with: If the volume is constant (dV = 0), we can paraphrase the first law as follows: And replace this in our specific heat equation with → or thermodynamics M. D. Eastin 4 Conservation of energy The first law of thermodynamics states that the total energy of each thermodynamic system is conserved → energy cannot be created or destroyed→ Energy does not can change only from one form to another Our main concern in meteorology. Thermodynamics M. D. Eastin 3 Forms of energy Internal kinetic potential Mechanical heat Energy comes in various forms.
Internal kinetic potential Mechanical heat Chemical thermodynamics Electrical thermodynamics M. D. Eastin PowerShow.com is a leading presentation sharing website. It has already downloaded and made available millions of presentations, with another 1,000 uploaded daily by its users. Whatever your area of interest, you can find and watch presentations you like here and possibly download. And the best part is that it is completely free and easy to use. 20 Heat capacities (specific heats)Specific heat at constant pressure: On this basis, and recognizing that we can obtain another alternative form of the first law of thermodynamics: also Thermodynamics M. D. Eastin 2 Thermodynamic processA thermodynamic process is a process in which heat is added or extracted from a system. ΔQ = heat change Each system has an internal energy state (ΔU). The energy state is defined by system temperature (T), volume (V) and pressure (P).
17 Heat capacities (specific heats)Suppose that a small amount of heat (dQ) is supplied to a package of constant mass (m). The packaging reacts with a slight increase in temperature (dT) Specific heat (C): Two types of specific heat: Depends on how the material changes when it receives heat Constant volume: Constant pressure: The package does not undergo any change in volume The package does not undergo any change in pressure Thermodynamics M. D. Eastin Something went wrong! Please try again and reload the page. 1 First law of thermodynamicsPlease drop off your labs at the front of the room Take out a sheet of paper No need for notes!. 15 Joule Law Air Valve Open Air Expands to Fill the VesselVolume Change Pressure Change No External Work has been done air expanded into a vacuum within the System No Heat Added or Subtracted ThermalLy Insulated System No Change in Internal Energy No Temperature Change What Does Mean About This Means? Valve Open Air Thermodynamics M. D. Eastin 11 First Law in “Brief”Here is a diagram of a generic thermodynamic process. A system has an initial internal energy. Heat (Q): can be added to the system or removed from the system or there can be no heat transfer.
Work (W): can be run on the system or the system can do work or there can be no work involved at all. 21 Concept of enthalpy Suppose: Heat (dQ) is added to a constant pressure system Effect: ) The volume of the system increases (V1→V2) and the work is done 2) The internal energy of the system increases (U1→U2) With the first law: We can then define enthalpy (H) as: Thermodynamics M. D. Eastin Physics 213: Conference 3, Pg 1 Package 3.4 Thermodynamics Thermodynamics l W = PΔV l 1st law of thermodynamics: ΔU = Q – W l Define: Adiabatic, 24 types of processes p i f V p i f V Isobaric processes:Constant pressure transformations dp = 0 Isochore processes: Constant volume transformations dV = 0 dα = 0 p i f V p i f V Thermodynamics M. D. Eastin 10 Pressure-volume (PV) diagramsA different way to represent thermodynamic processes: Consider the transformation: I → f p f pf i pi Vi Vf V Thermodynamics M.D. Eastin PowerShow.com is brought to you by CrystalGraphics, the award-winning developer and market-leading publisher of rich media enhancement products for presentations. Our product offering includes millions of PowerPoint templates, graphics, animated 3D characters, and more. 2 First law of thermodynamicsStructure: Forms of energy saving Work concept PV diagrams Internal energy concept Joule`s law Thermal capacities (specific heats) Concept of enthalpy Various forms of the first law Types of processes Thermodynamics M. D.
Eastin 6 The concept of work Work is a mechanical form of energy: Remember the definition of pressure: So we can define work as: Thermodynamics M.D. Eastin 8 When we discuss these laws, think about….. Zeroth: The temperature exists and that`s why you have to play the game. The heat will always change from hot to cold. First of all, you can`t win. You can`t get more energy from a heat engine than you put into it. Second, you can`t break even. No heat engine can use all the heat produced by a fuel for work.
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