Concept explainers
a)
The amount of heat transfer for the dissociation of water.
a)
Answer to Problem 48P
The amount of heat transfer for the dissociation of water is
Explanation of Solution
Write the expression for the stoichiometric reaction for reaction 1.
Here, the stoichiometric coefficient for
Write the expression for the stoichiometric reaction for reaction 1.
Here, the stoichiometric coefficient for
Write the expression for the actual reaction for the reported process.
Here, the equilibrium composition contains x kmol of
Write the hydrogen balance equation From Equation (III).
Write the oxygen balance equation From Equation (III).
Write the expression for the formula for total number of moles
Here, number of moles of
Write the expression for the equilibrium constant for reaction 1
Here, pressure is P.
Write the expression for the equilibrium constant for reaction 2
Write the energy balance equation to determine the heat transfer
Here, number of moles of products is
Write the expression to calculate the molar flow rate of water
Here, mass flow rate of water is
Write the expression to calculate the rate of heat transfer
Conclusion:
Refer Table A-28, “Natural logarithm of equilibrium constants”, select the value of
Refer Table A-28, “Natural logarithm of equilibrium constants”, select the value of
Substitute x for
Substitute
Substitute
Solve Equations (IV), (V), (XII), and (XIII) simultaneously and find the values of x, y, z, and w, as 0.7835, 0.1622, 0.05396, and 0.1086 respectively.
Substitute 0.7835 for x, 0.1622 for y, 0.05396 for z, and 0.1086 for w in Equation (III).
Refer the table A-26, “Enthalpy of formation table”, obtain the enthalpy of
Refer the table A-23, “Ideal gas properties of water vapor”, obtain the enthalpy of water vapor at 3000 K
Refer the table A-22, “Ideal gas properties of
Refer the table A-19, “Ideal gas properties of
Refer the table A-25, “Ideal gas properties of
Write the heat input equation
Here, number of moles of product is
Substitute
Substitute
Substitute
Thus, the amount of heat transfer for the dissociation of water is
b)
The amount of heat transfer for the absence of dissociation of water.
b)
Answer to Problem 48P
The amount of heat transfer for the absence of dissociation of water is
Explanation of Solution
Write the expression to determine the heat transfer for the absence of dissociation of Water.
Conclusion:
Substitute
Thus, the amount of heat transfer for the absence of dissociation of water is
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Chapter 16 Solutions
Thermodynamics: An Engineering Approach
- An iron-carbon alloy initially containing 0.268 wt% C is exposed to an oxygen-rich and virtually carbon-free atmosphere at 1040°C. Under these circumstances the carbon diffuses from the alloy and reacts at the surface with the oxygen in the atmosphere; that is, the carbon concentration at the surface position is maintained essentially at 0.0 wt% C. At what position will the carbon concentration be 0.201 wt% after a 7 h treatment? The value of D at 1040°C is 2.5 × 10-¹1 m²/s. erf(z) erf(z) 0.55 0.5633 1.3 0.025 0.0282 0.60 0.6039 1.4 0.9523 0.0564 0.65 0.6420 1.5 Z 0.00 0.05 0.15 0.0000 0.10 0.1125 0.70 0.6778 0.20 Z 0.1680 0.75 0.7112 1.7 0.2227 0.80 0.7421 1.8 0.45 0.4755 1.1 0.50 0.5205 Z 1.6 1.2 0.9103 erf(z) 0.9340 2.8 0.9661 0.25 0.2763 0.85 0.7707 1.9 0.9928 0.30 0.3286 0.90 0.7970 2.0 0.9953 0.35 0.3794 0.95 0.8209 2.2 0.40 0.4284 1.0 0.8427 2.4 0.9763 0.9838 0.9891 0.9981 0.8802 2.6 0.9998 0.9993 0.9999arrow_forwardWhen a 13.0-g sample of NaOH(s) dissolves in 400.0mL of water in a coffee cup calorimeter, the temperature of the water changes from 22.6°C to 30.7°C. Assuming that the specific heat capacity of the solution is the same as water, calculate (a) the heat transfer from system to surroundings and (b) ΔH for the reaction.NaOH(s)→Na+(aq)+OH-(aq)arrow_forwardA sheet of steel with 3.5-mm thickness has a nitrogen atmospheres on both sides at 900°C and is permitted to achieve a steady-state diffusion condition. The diffusion flux is found to be (1.0 ×10^-7 )kg/m^2×second.Also it is known that the concentration of nitrogen in steel at the high-pressure surface is 2 kg/m^3.How far into the sheet from this high-pressure side will the concentration be 0.5 kg/m^3?Assume a linear concentration profile.arrow_forward
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