If the inventory of the reactor of about 20,000kg

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Discussion Overview

The discussion revolves around a homework problem involving the oxidation of zirconium (Zr) by steam, focusing on the calculations of heat generated, hydrogen produced, energy released from combustion, and pressure changes in a reactor. Participants explore stoichiometric relationships, ideal gas behavior, and the implications of their calculations.

Discussion Character

  • Homework-related
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant calculates the heat generated from Zr oxidation as 13.5x10^3 MJ based on the given reaction and parameters.
  • Another participant suggests that the volume fraction of hydrogen should consider both remaining water and produced hydrogen, proposing a temperature of 100°C for calculations.
  • Discussions on the ideal gas law are raised, with participants confirming the total volume of the reactor as 90,000 m³.
  • Several participants debate the correct stoichiometric relationships, with one asserting that the mass of hydrogen produced should be calculated using stoichiometry rather than enthalpy change.
  • Participants express confusion over the correct number of moles of hydrogen produced, with varying interpretations of stoichiometric coefficients leading to different conclusions.
  • One participant correctly identifies the number of moles of Zr in 20,000 kg and calculates the corresponding moles of hydrogen produced, but others challenge the accuracy of their calculations and units used.
  • There is a recurring emphasis on the importance of using consistent units and correctly interpreting stoichiometric coefficients in the context of the reaction.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the calculations, with multiple competing views on the correct approach to stoichiometry and the resulting quantities of hydrogen and energy. Disagreements persist regarding the interpretation of the reaction and the application of the ideal gas law.

Contextual Notes

Participants express uncertainty about the correct application of stoichiometric principles and the implications of their calculations, indicating a need for clarity on the relationships between mass, moles, and gas behavior in the context of the reaction.

Who May Find This Useful

This discussion may be useful for students studying chemical engineering, chemistry, or related fields, particularly those interested in stoichiometry and gas laws in reaction contexts.

  • #31


20,000 of what? 91.2 of what?

20,000kg and 91.2 kg/kmol
 
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  • #32


matt222 said:
20,000kg and 91.2 kg/kmol

If so - that's OK. Note that you wrote a line earlier "1 mole of Zr=91.2g/mol", so it wasn't clear what you use.
 
  • #33


what about part 3 of the question is ok?

for part 4 I got the idea now:

PV=nRT

P=nRT/V=(43.86 kmoles x 8.31x10^3 (m^3pa/kmol k) x 373K)/90,000m^3=1511pa

so the pressure increased is going to be 1.015bar!

what do you think?
 
  • #34


Change in pressure is a function of change of number of moles of gas.

What gases are present? How does their amount change?
 
  • #35


the gases are hydrogen and air and the question asked me to treat it as ideal gases!

ΔPV=ΔnRT, but how could we get the change of n since no information given for the air!

their amount will be changed due to pressure increase or decreased
 
  • #36


Judging from the question there is no air involved, just water steam and hydrogen. But even if there is air present - does amount of air change?
 
  • #37


no it doesn't change!

so in this case I should measure the change on n between water steam and hydrogen gas right!
 
  • #38


Yes.
 
  • #39


we had already measured n for the hydrugen , now as before should I do the balance equation and find n for 2H20, after that add them together to have total n,
 
  • #40


matt222 said:
we had already measured n for the hydrugen , now as before should I do the balance equation and find n for 2H20

Yes - and no. Yes, that's the correct approach. No, you don't have to do it. Just looking at the reaction equation coefficients you should see that water/hydrogen ratio is 1 - number of moles of hydrogen produced equals number of moles of water consumed. As you have already calculated number of moles of hydrogen, you don't have to calculate number of moles of water - it will be the same number.

after that add them together to have total n,

Beware about adding - water is consumed, so it is removed from the reactor.
 
  • #41


so how to get the change of n now?
 
  • #42


I have spoonfeed you for almost three pages, my hand hurts. It is the highest time you start to think on your own. Especially taking into account fact that what you are asking about now has nothing to do with chemistry, common reasoning is enough.
 
  • #43


of course I appreciate your help but you will be shocked if I tell you that I am a computer science background and moved to this field just recently that's why I need a time
 

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