Explore BrainMass

Explore BrainMass

    Internal Energy

    Internal energy is the total energy contained by a thermodynamic system. It is the energy required to create the system but remove the energy to displace the system’s surroundings, any energy connected with a move as a whole. The internal energy of a system can be changed by heating or cooling the system. The first law of thermodynamics states that an increase in internal energy is equal to the total heat added and work done by the surroundings.Therefore if a system is isolated, the internal energy cannot change.

    Internal energy is a state function of a system because its value depends only on the current state of the system and not on the path taken or process underdone to arrive at the state. It is an extensive quantity. The SI unit of internal energy is a joule (J). Specific internal energy is the internal energy per unit of mass of the system in question.
    Internal energy can be calculated by:

    U= U_pot+ U_kin

    And the change in internal energy is

    ∆U=Q+ W_mech+ W_extra

    © BrainMass Inc. brainmass.com March 31, 2023, 5:23 am ad1c9bdddf


    BrainMass Categories within Internal Energy

    System Work

    Solutions: 44

    Work is the energy transferred by a system to another.

    First Law of Thermodynamics

    Solutions: 54

    The first law of thermodynamics states that the internal energy of an isolated system will remain constant and the energy cannot be destroyed.

    BrainMass Solutions Available for Instant Download

    Analysis of Internal Energy Changes, Catalysts and pH

    More modern fireworks replace potassium nitrate with potassium chlorate. The thermochemical equation for the decomposition of potassium chlorate is shown in Equation 1. Often a catalyst is added to speed up this reaction. Equation 1: 2KClO3(s) = 2KCl(s) + 3O2(g) ?H = -89.4 kJ mol-1 For reaction 1 draw a fully labelled diagr

    Heat capacity and work done by various systems

    Questions: a. Calculate the heat capacity of a radiator coolant if a temperature rises from 5 to 107 °C requires 932 J of heat. b. What is the change in internal energy for a system that does 7.02 kJ of work and absorbs 888 J of heat?

    Entropy Change and Maximum Work Problem

    Consider a thermally isolated system that consists of a body at temperature T1 and a large reservoir at temperature T2 > T1. The reservoir is sufficiently large so that its temperature does not change. The body has constant pressure heat capacity of Cp that does not vary with temperature. Please explain to me how to obtain t

    Thermodynamics: Enthalpy Change

    Hi, hope you can help. bond molar bond enthalpy/kj mol^-1 N-H 392 H-H 436 N=N (triple bond) 945 reaction 1: N2 (g) + 3H2 (g) = 2NH3(g) Use the molar bond enthalpies above to show the overall enthalpy change for reaction one is -93kj mol^-1 show a

    Waves and oscillations

    A sound source sends a sinusoidal sound wave of angular frequency 3000 rad / s and amplitude 12.0 nm through a tube of air. The internal radius of the tube is 2.00 cm. (a) What is the average rate at which mechanical energy is transported to the opposite end of the tube? If an identical wave and the original wave travel alon

    Helmholtz free energy problem

    The Helmholtz free energy is given by F = U - TS (a) What is the natural (independent) variables of the Helmholtz free energy F? (b) Show that the differential of the Helmholtz free energy F is a function of its natural variable only. (c) Show that for fixed mole numbers, fixed temperature and fixed volume, the Helmho

    Determining Solutions for Example Physics Problems

    1. How many calories are needed to raise 500 grams of water from 25 degrees Celsius to 40 degrees Celsius? 2. Define the following terms: a. Internal energy b. Specific heat c. Entropy d. Temperature 3. Suppose a 1 meter long bar expands 0.5 centimeters when heated. By how much will a 100 meter long bar of the sam

    Thermal Physics Entropy

    An ideal gas has a specific heat given by Cv = A+BT, where A and b are constants. Show that the entropy per kilo-mole in going from state (v1,T1) to state (v2,T2) is: delta(s) = A ln (T2/T1)+ B(T2-T1)+ R ln (v2/v1).

    Heat capacity of a 2d electron gas and of a 2d phonon gas.

    What physical conditions lead electrons in a metal to form a degenerated Fermi gas? Show that the density of states for an ideal two-dimensional Fermi gas of particle with spin 1/2 and mass m that occupies area A is: g(E)=(A/2pi)(2m/h^2) Obtain a relationship between the number of electrons per unit area and the Fermi ene

    First law of thermodynamics

    Show that under certain conditions, that you should state, dQ = cp dt - V dp for unit mass of an ideal gas. (Please also see the attachment)

    Thermodynamic process problem

    A The drawing refers to one mole of a monatomic ideal gas and shows a process that has four steps, two isobaric (A to B, C to D) and two isochoric (B to C, D to A). Complete the following table by calculating U, W, and Q (including the algebraic signs) for each of the four steps and for the whole process.

    Heat and Thermodynamics: Monoatomic to diatomic

    Initially, a quantity of a mono atomic gas (cv=3R/2) occupies a rigid container with volume V=0.19m^3. The temperature and pressure are Ti=287k and Pi=108Kpa. The gas reacts completely with itself to form half the original moles of a diatomic gas (cp=5R/2). The reaction is exothermic and produces an amount of heat Q=36497 J whic

    Heat and Thermodynamics: Change in internal energy.

    A cylinder (cross section is 0.2m2) with a free moving piston is filled with gas. The piston is attached to a heavy weight W = 10000N. Outside the cylinder, the air is at 300K and 1 atm. Initially the gas is at 300K, then it is heated to 400K. The heat capacity of the gas under the constant pressure is 500J/K. If the length of

    Debye Model of Lattice Specific heat

    The lattice specific heat of solids based on the Debye model. Classical theory and its failure Einstein model of specific heat , assumptions, formulation and advantage Debye model of lattice specific Heat,assumptions, formulation and advantages The merits as well as the drawbacks of both models. explanatios of terms Refe

    Global Management

    Research Chevron (http://www.chevron.com). Using your research findings from the Library and the Internet, develop both an EFAS (External Factors Analysis Summary) table and an IFAS (Internal Factors Analysis Summary) table.

    Heat and Thermodynamics:Entropy change in Isothermal process

    One mole of an ideal gas is contained in a thermally insulated container that is connected to another container of equal volume that is initially evacuated. The valve connecting the two containers is now opened and the gas allowed to expand isothermally to fill both sides - new total volume is twice original volume. A) What i

    application of work-energy theorem

    In the figure, two blocks are connected by a string across a pully. m1 sits at rest on a table. m1 = 3.4 kg. Use work and energy to find the speed of the m2 = 2.5 kg block just before it hits the floor in each of the following cases. * Distance between the floor and m2 = 1.5 (a) The table is frictionless. (b) The coef

    Mixing of Liquids: Temperature and Energy

    Two volumes V1 and V2 of the same incompressible liquid at temperatures T1 and T2 are mixed together in a thermally isolated container. When equilibrium is reached, the mixtures is at a temperature Tmix. If instead a reversible heat engine were operated between the two volumes of liquid until they reached the same temperature, s

    Energy and work done by a gas system

    An insulated cylinder closed at one end by a frictionless piston contains 20g of hydrogen gas at 30 degrees Celsius. This is heated to 40 degrees Celsius with the pressure kept constant at 1 bar and the volume increases by 7*10^-4 m^3. (The specific heat of H2 at constant pressure is 1.4*10^4 JKg^-1 K^-1). a) What is the wor

    Applying to Ideal Gas Equation

    In our course lab, our experiment required us to take wood fibers and mix them into a slurry in which that slurry was 65% water content. We then formed the slurry into a brick and placed it in a small electric lab press where variable hydraulic pressure and heat energy was applied to this wet wood brick. Using a thermocouple

    Change in internal energy

    What is the change in internal energy of a system that has 655 J of work done on it and gives off 515 J of heat? (in J)

    Canonical Ensemble

    Prove that k sum over r of P_r Log(P_r) for the canonical ensemble. See attached file.