PA7 - Problem Analysis#7 Material and Energy Balance(March...

Info icon This preview shows page 1. Sign up to view the full content.

Problem Analysis #7: Material and Energy Balance (March 16) Problem 1. Heat capacity and enthalpy The heat capacity of substance is often expressed as a function of temperature using a polynomial: C p = a + bT + cT 2 + dT 3 The following values have been reported for water vapor for T in C and Cp in J/mol× C: a = 33.46 b = 0.688×10 -3 c = 0.7604×10 -5 d = -3.593×10 -9 a. Calculate the enthalpy of water vapor at 1500 C in relative to water vapor at 25 C. b. Calculate the enthalpy of water vapor at 1500 C in relative to liquid water at 0 C if H v of H 2 O at this temperature is 2500kJ/kg. [ Note: We learnt in class that C p does not vary greatly in narrow temperature ranges (try to prove this statement by calculating C p at different T values using the above polynomial). Therefore, unless stated otherwise, it can be assumed that C p is a constant in many problems.] Problem 2. Enthalpy of humid air Enthalpy, H = U + pV, has no absolute value; only changes in enthalpy can be calculated. To simplify H and, therefore,
Image of page 1
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern