Homework Help is Here – Start Your Trial Now!
Engineering
Chemical Engineering
Example 2.6-2 Dimensional Homogeneity and Dimensionless Groups (a) The Nernst equation is used to predict the voltage in a fuel cell as a function of the partial pressure of the gases. This formula can be rearranged to give: P,P2 H2 02 [2F(E-E,) Pu20 P2 RT If F has units of C/mol e', E and Eo have units of V, R has units of J/mol H,-K, and T has units of K, then what are the units on the constant 2? Strategy We can compare the prescribed units to determine the unknown units. Solution The term in the natural log must be dimensionless. Thus, noting that 1 V = 1 J/C, we can solve for the units on 2 as: J -K mol H, - K C J mole C RT mol F(E-E,) mol (b) A dimensionless group in heat transfer is the Prandtl number, given by: µC, Pr k

Example 2.6-2 Dimensional Homogeneity and Dimensionless Groups (a) The Nernst equation is used to predict the voltage in a fuel cell as a function of the partial pressure of the gases. This formula can be rearranged to give: P,P2 H2 02 [2F(E-E,) Pu20 P2 RT If F has units of C/mol e', E and Eo have units of V, R has units of J/mol H,-K, and T has units of K, then what are the units on the constant 2? Strategy We can compare the prescribed units to determine the unknown units. Solution The term in the natural log must be dimensionless. Thus, noting that 1 V = 1 J/C, we can solve for the units on 2 as: J -K mol H, - K C J mole C RT mol F(E-E,) mol (b) A dimensionless group in heat transfer is the Prandtl number, given by: µC, Pr k

Introduction to Chemical Engineering Thermodynamics
Introduction to Chemical Engineering Thermodynamics
8th Edition
ISBN:9781259696527
Author:J.M. Smith Termodinamica en ingenieria quimica, Hendrick C Van Ness, Michael Abbott, Mark Swihart
Publisher:J.M. Smith Termodinamica en ingenieria quimica, Hendrick C Van Ness, Michael Abbott, Mark Swihart
Chapter1: Introduction
Section: Chapter Questions
Problem 1.1P
See similar textbooks
icon
Related questions
Question
100%
Answer those blanks. Show complete solutions. (Chemical Engineering Calculations)
Example 2.6-2 Dimensional Homogeneity and Dimensionless Groups (a) The Nernst equation is used to predict the voltage in a fuel cell as a function of the partial pressure of the gases. This formula can be rearranged to give: 2F(E - E,) = In PH20 P12 RT If F has units of C/mol e', E and Eŋ have units of V, R has units of J/mol H2-K, and T has units of K, then what are the units on the constant 2? Strategy We can compare the prescribed units to determine the unknown units. Solution The term in the natural log must be dimensionless. Thus, noting that 1 V = 1 J/C, we can solve for the units on 2 as: J K mol H, – K RT mol F(E – E,) J mol mole C (b) A dimensionless group in heat transfer is the Prandtl number, given by: Pr = k If C, has units of J/g-K and k has units of W/m-K, then what are the units on the viscosity Strategy We can compare the prescribed units to determine the unknown units. Solution Noting that 1 W = 1 J/s, we can solve for the units on µ as: k W g-K J/s m -K J W
Transcribed Image Text:Example 2.6-2 Dimensional Homogeneity and Dimensionless Groups (a) The Nernst equation is used to predict the voltage in a fuel cell as a function of the partial pressure of the gases. This formula can be rearranged to give: 2F(E - E,) = In PH20 P12 RT If F has units of C/mol e', E and Eŋ have units of V, R has units of J/mol H2-K, and T has units of K, then what are the units on the constant 2? Strategy We can compare the prescribed units to determine the unknown units. Solution The term in the natural log must be dimensionless. Thus, noting that 1 V = 1 J/C, we can solve for the units on 2 as: J K mol H, – K RT mol F(E – E,) J mol mole C (b) A dimensionless group in heat transfer is the Prandtl number, given by: Pr = k If C, has units of J/g-K and k has units of W/m-K, then what are the units on the viscosity Strategy We can compare the prescribed units to determine the unknown units. Solution Noting that 1 W = 1 J/s, we can solve for the units on µ as: k W g-K J/s m -K J W
Expert Solution
trending now

Trending now

This is a popular solution!

steps

Step by step

Solved in 4 steps with 4 images

SEE SOLUTIONCheck out a sample Q&A here
Blurred answer
Recommended textbooks for you
Introduction to Chemical Engineering Thermodynami…
Introduction to Chemical Engineering Thermodynami…
Chemical Engineering
ISBN:
9781259696527
Author:
J.M. Smith Termodinamica en ingenieria quimica, Hendrick C Van Ness, Michael Abbott, Mark Swihart
Publisher:
McGraw-Hill Education
Elementary Principles of Chemical Processes, Bind…
Elementary Principles of Chemical Processes, Bind…
Chemical Engineering
ISBN:
9781118431221
Author:
Richard M. Felder, Ronald W. Rousseau, Lisa G. Bullard
Publisher:
WILEY
Elements of Chemical Reaction Engineering (5th Ed…
Elements of Chemical Reaction Engineering (5th Ed…
Chemical Engineering
ISBN:
9780133887518
Author:
H. Scott Fogler
Publisher:
Prentice Hall
Process Dynamics and Control, 4e
Process Dynamics and Control, 4e
Chemical Engineering
ISBN:
9781119285915
Author:
Seborg
Publisher:
WILEY
Industrial Plastics: Theory and Applications
Industrial Plastics: Theory and Applications
Chemical Engineering
ISBN:
9781285061238
Author:
Lokensgard, Erik
Publisher:
Delmar Cengage Learning
Unit Operations of Chemical Engineering
Unit Operations of Chemical Engineering
Chemical Engineering
ISBN:
9780072848236
Author:
Warren McCabe, Julian C. Smith, Peter Harriott
Publisher:
McGraw-Hill Companies, The
SEE MORE TEXTBOOKS