Physical chem Definition and 24 Threads

  1. CatalinaAlmendra

    Chemistry How Does Surface Area Affect the Free Energy of a Liquid?

    Hello, so first of all I want to clarify that english is not my first lenguage, so I'm really sorry for possible future errors. Second, this is a problem from my physical chemistry class, and I'm not sure where it fits better, if here or in the physics homework help, I'm sorry :( So, I don't...
  2. Y

    Low-Temp Liquid Helium System: Evaporation Heat & Temperature

    We consider a system composed of liquid helium in equilibrium with its vapor at very low temperature T, each phase being considered extensive. We neglect the mass of the gas compared to that of the liquid, as well as the heat capacities of the gas and the walls compared to that of the liquid...
  3. S

    How to calculate the transition temperature in this problem?

    Summary: The transition Sn(s, gray) ⇌ Sn(s, white) is in equilibrium at 18°C and 1 atm pressure. If ΔS = 8.811K mol for the transition at 18°C and if the densities are 5.75 g/cm3 for gray tin and 7.28 g/cm3 for white tin, calculate the transition temperature under 100 atm pressure The...
  4. felipeborges

    Estimating the Evaporation Rate

    So I must define the problem stated above. I must define the variables and the error associated with each one of them. Any Formula, Articles, Insight would be of great help! Thanks in advance.
  5. V

    Calculate Mass of Non-Volatile Solute in Octane to Reduce V.P. 80%

    I've got this, calculate the mass of a non volatile solute (molar mass 40) that should be dissolved in 114 g of octane to reduce its vapour pressure to 80 percent I do this, v.p = v.p_pure * mole fraction of solvent in solution we have 1 mole of solvent and let's take n moles of substance so...
  6. B

    Kinetics question (Chemical engineering)

    Hey! I have a question regarding this question that I have to answer. It is about the kinetics of a substance X whose product is 2Y. It is in Swedish and here is the translation: The absorbance of a 0,030M-solution of X was calculated with the help of a Spectrometer. The Spectrometer was...
  7. IoFawkes

    Calculate Work (w) for Isothermal Gas Expansion/Compression

    Homework Statement Calculate Work(w) when 6.5L of an ideal gas at an initial pressure of 34.3atm is expanded or compressed isothermally to a final volume of 34.3L reversibly. Answer in J Homework Equations PV=nRT P1V1=P2V2 w=-nRT In(V2/V1) The Attempt at a Solution Using w=-nRT In(V2/V1) I'm...
  8. sara lopez

    Thermodynamics: air expansion in a cylinder

    Homework Statement Consider air expansion inside a cylinder. Assume that the volume and initial pressure is 1 ft^3 and 1500 PSI ABS respectively. If the expansion process is reversible and the path is given by P.V^1.4=constant. Calculate the total work done by the gas to reach the final volume...
  9. Ariel Jo

    What is the standard free energy change for the decomposition of pyruvic acid?

    Homework Statement Consider the reaction of pyruvic acid (CH3COCOOH) into gaseous acetaldehyde (CH3CHO) and gaseous CO2, which is catalyzed an aqueous solution by the enzyme pyruvate decarboxylase. Assume ideal gas behavior only for the CO2. (a) Calculate ∆298 0 for this reaction. (b) Calculate...
  10. Ariel Jo

    Supercooled Steam Homework: Solving for Tf, Condensation Fraction & ΔS

    Homework Statement You have 0.50 mol of steam which has been supercooled to 95˚C at 1 atm. Since the steam is below the boiling/condensation point, it proceeds to partially condense into liquid water. This happens in a thermally-insulated vessel at constant pressure. (a) When the system...
  11. Ariel Jo

    Calc ∆Ho & ∆Eo for CH3OH Reaction @ 298K

    Homework Statement For the reaction CH3OH(l) → CH4 (g)+ 1/2 O2 (g)[/B] (a) Calculate ∆Ho298 (b) Calculate ∆Eo298 (c) Write an equation that would allow you to determine ∆H at 500°C and 1atm Homework Equations ∆H=∆E+∆(PV) ∆H=Σ∆Hproducts-Σ∆Hreactants The Attempt at a Solution a)...
  12. T

    Which Gas Has the Highest Vibrational Molar Heat Capacity at 50K?

    Number 1 For the gas phase reaction, cyclopentene + I2 = cyclopentadiene + 2HI, we find that ln Kp = 7.55 - (4817K / T) (where the symbol K on the right hand side refers to the units Kelvin). What are the changes in entropy and enthalpy? Possible answers are ΔSo = 40.05 kJK-1mol-1 and...
  13. A

    Programs Chemistry Major: Am I on track for Physical Chem?

    So I am a Chemistry major, but am behind on my math (was a Biology major but switched because I decided I would rather minor in Biology so as to avoid the boring plant and evolution/ecology stuff, plus I love Chemistry lol) and so am only taking calculus II this coming semester. My adviser wants...
  14. F

    Schools Physical Chem vs. CM physics Graduate school

    I'm currently applying for various graduate schools in both physical chemistry and condensed matter physics. My undergraduate degree is a double major in both fields. I'm curious about what the differences between the departments (and, to an extent, fields) might be. In terms of research...
  15. G

    Physical Chem Van der Waals eqn of state

    Homework Statement Use the “virial equation of state”. Measurements for Ar gave B = -21.7 cm3/mol and C = 1200 cm6 /mol-2. Assuming that Ar is a van der Waals-type gas, what are the values of “a” and “b” in the corresponding van der Waals equation of state Homework Equations PV= RT(1+...
  16. C

    Volume and Diameter Increase of Balloon in Stratosphere: Physical Chem Question

    Homework Statement Calculate the factor by which the volume and the diameter of a balloon would increase as it rose from sea level and 20 degrees celsius to the stratosphere at 40km. Homework Equations PV=nRT The Attempt at a Solution I don't think I have enough information to solve?
  17. M

    Does Quantum Mechanics contain Physical Chem?

    I'm not sure whether to just take Physical Chemistry because I'm interested in it or should I just take Quantum Mechanics? I've already taken Thermodynamics and I heard P-Chem is Thermo and Quantum combined. Is Quantum more in-depth than P-chem?
  18. J

    Physical Chem Question - Xrays & Crystals

    [Xray reflection 1. Homework Statement X-rays of 1.54 angstroms are reflected off copper powder @ 21.65º 25.21º 37.06º 44.96º 47.58º Find the cubic lattice and the length of an edge of the unit cell. 2. Homework Equations nλ = 2d sin(Θ) ; the Bragg equation 3. The...
  19. C

    Physical Chem, work of a non-ideal gas

    I have a problem where I am given an equation of state pV=RT+(bRT-a)/V and asked to find the work produced in the isothermal, reversible expansion from V1 to V2. I thought I would want to use W=-integral(nRT/V)dV, but that is apparently only for ideal gases, and this problem concerns a...
  20. L

    Isothermal and reversible expansion work problem (Physical Chem)

    Homework Statement A sample of 2.00 mol. CH3OH (g) is condensed isothermally and reversibly to liquid at 64*C. The standard enthalpy of condensation of methanol @ 64*C is -35.3 kJ/mol. Find w and q for the reaction. Homework Equations w = -nRT * ln(Vf/Vi) (although I don't have volume...
  21. N

    Thermodynamics physical chem related questions

    What an awesome site. Well I was wondering, i have a bunch of thermodynamics physical chem related questions to ask, where is the best place to ask them? are any of you good at thermodynamics, are there any experts here? :approve:
  22. L

    Programs How valuable would physical chem 1 and 2 be for a physics major?

    technically, I only need one or the other to pick up my chem minor, but I might take both. How valuable would they be to a physics major planning to go to graduate school? I would like to take them both, but would grad schools care all that much? I am honestly not sure where I want to do...
  23. S

    Confused about Physical Chemistry Calculations?

    Hello,there are some question about physical chemistry to be asked. :-p 1) The space vehicle,Gemini,started its journey in space with 322kg of liquid fuel, CH3NHNH2. This fuel is oxidised by dinitrogen tetroxide,N2O4,to form nitrogen,carbon dioxide and water.hat is the mass of...
  24. D

    Why Do Dicarboxylic Acids Show a Less Pronounced Odd-Even Effect in pKa?

    Hi everyone :smile: I need help to answer these question related to physical chemistry : 1- In reaction Kinetics, what reaction takes place during titration? 2- In reaction kinetics, why do we use a water bath? 3- Why Dicarboxylic acids do not show a clear odd-even effect in pKa...
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