thermodynamics

  1. S

    Phase equilibria, Physical Chemistry

    At 25°C we have for rhombic sulfur: ΔfG°= 0; S° = 31.88 ± 0.17 J /K/ mol ; and for monoclinic sulfur: ΔfG°=63 J/mol; S°= 32.55 ± 0.25 J/K/mol. Assuming that the entropies do not vary with temperature, sketch the value of 'μ' versus T for the two forms of sulfur. From the data determine the...
  2. S

    Phase equilibria, Physical Chemistry

    At 25°C we have for rhombic sulfur: ΔfG°= 0; S° = 31.88 ± 0.17 J /K/ mol ; and for monoclinic sulfur: ΔfG°=63 J/mol; S°= 32.55 ± 0.25 J/K/mol. Assuming that the entropies do not vary with temperature, sketch the value of 'μ' versus T for the two forms of sulfur. From the data determine the...
  3. N

    A question about thermodynamics

    I'm not sure what the answer is, all of my friends and my chemistry teacher said it is A, I think it is obvious that the graph is talking about 2 catalysts so it could be D. But I have no idea what the E_a thing is, I've tried googling it to no avail. I got this question on an advanced...
  4. T

    Partial pressure and Gibbs free energy

    Hi everyone, i'm given the equation in the red zone in my attempt: NH4Cl<=>NH3+HCl at a temperature of 298K. I have to calculate what the partial pressure of HCl will be at the equilibrium of this reaction, starting only with NH4Cl in an closed room. In order to do this, I have to first...
  5. K

    Calculating PV work done at atmospheric pressure?

    I need some help figuring out this problem. This is the original problem: How much PV work is done in kilojoules for the reaction of 3.74 mol of H2 with 1.87 mol of O2 at atmospheric pressure if the volume change is −23.9L? And we are given this reaction: The reaction between hydrogen and...
  6. M

    Inorganic Chemistry

    Hi, Im just getting trouble doing this question 1, I dont know centanly what to do there, but my Professor told that I can solve this fist question if I have made de second one. The second was easy to solve by only solving de DH. I'm so stuked on this first question, thanks if you guys can help...
  7. H

    an open container with 10L of water at 1 bar and 20 C is used for cooling electronic

    an open container with 10L of water at 1 bar and 20 C is used for cooling electronic parts.Each electronic part has a mass of 01.kg and an average specific heat of 0.14 kJ/kg-K. The electronic parts are initially at 300 degrees Celcius and are required to be cooled to 80 degrees celcius without...
  8. P

    need some help with thermodynamics please..

    An ideal gas having initial pressure P,volume and temperature T is expanded adiabatically till its volume is 5.66V,while temperature falls to T/2.work done is xPV/4.find x. I have spent almost an hour on this question to no avail..please help.
  9. J

    Entropy

    Q] Calculate the change in molar entropy when a monoatomic gas is compressed from 2.0 dm^3 to 500 cm^3 and simultaneously heated from 300K to 400K. Take Cv,m = 3R/2. I tried splitting it into a) constant volume process and b0 constant temperature process and adding the two entropies but that...
  10. H

    Pharmacy calculations, thermodynamics and tonicity

    Hey guys any help with answering these questions and maybe some explanation would be greatly appreciated: 1. A first order reaction has a half-life of 1.98 days. The rate constant for the reaction is (a) 1.37 days-1 (b) 1972.80 minutes-1 (c) 0.35 days-1 (d) 0.35 mol days 2. The enzyme-catalysed...
  11. I

    Does this reaction have a critical temperature?

    2 CCl4 (g) + O2 (g) --> 2COCl2(g) + 2Cl2(g) Predict the sign of ΔS, as the reaction proceeds to the right: the products have a higher ΔS because there are more mols of gaseous products than reactants. ΔG and ΔH are also positive at room temp. (it's not spontaneous). So does this reaction have...
  12. B

    Chemistry thermodynamics?

    600.0 mL of 0.400 mol L–1 perchloric acid, HClO4(aq) was added to a high quality insulated calorimeter containing 400.0 mL of 0.600 mol L–1 KOH(aq). Both solutions had a density of 1.000 g mL–1 and a specific heat of 4.184 J g–1 K–1. The calorimeter had a heat capacity of 950.0 J K–1. The...
  13. wallythewalrus

    derive an expression for the contribution of:

    Derive an expression for the contribution to the molar heat capacity at constant volume CV,m(T) of Cl atoms from these electronic states and evaluate it for T = 500 K. THEORY: The electronic ground state of the Cl atom is fourfold degenerate, while the first electronically excited state is...
  14. P

    Thermodynamics Question: Finding Equilibrium Constant

    Calculate the standard free energy change for the combustion of methanol at 25 deg. C. 2 CH3OH(l) + 3 O2(g) -> 2 CO2(g) + 4 H2O(g) My answer was -1.37E3 kJ, which was right. Now the part I need some guidance on: If instead of the theoretical 2 mol, the actual reaction uses reaction...
  15. M

    thermodynamics!!

    how is the lattice enthalpy, enthalpy of hydration and enthalpy of solution related mathematically? Really am stuck!
  16. C

    Thermodynamics

    Which term, the standard molar entropy( delta S knot) or the standard free energy (delta G know) is the most important in determining the relative strength in the series of acids? I have been stuck on this question for a while, both terms tell us how spontaneous a reaction is, which one is more...
  17. S

    Thermodynamics Help!

    Please, any help with the following questions would be awesome! :D And you guys don't have to answer the WHOLE thing, like i said....any help would be awesome! :) 1. Carbon reacts with liquid oxygen to form carbon dioxide according to the reaction: C(s) + O2(l) -> CO2(g) Assume 2.00-gal of...
  18. M

    Thermodynamics Exercise Again

    A 45.0g spoon is heated to 1 00°C in boiling water and is dropped into a coffee cup calorimeter containing 50.0g of water at 25.0°C. If the final water temperature is, 28.6°C, calculate the specific heat capacity of the spoon. Is the spoon stainless steel or silver?
  19. M

    Thermodynamics

    When aluminum metal is exposed to atmospheric oxygen (as in aluminum doors and windows), it is oxidized to form aluminum oxide. How much heat is released by the complete oxidation of 24.2 grams of aluminum at 25°C and 1 atm? The thermochemical equation is 4Al(s) + 3O2(g) -------- > 2Al2O3(s) H =...