Help on question about Haber Process (1 Viewer)

EViL.GENiUS · May 27, 2009

1. The gases go into the reactor in a nitrogen:hydrogen volume ratio of 1:3. Explain why this means that the gases go into the reactor in a ratio of one molecule of nitrogen to three molecules of hydrogen.

2. What compromise is reached about the temperature used for the process? Why is this compromise needed?

3. What compromise is reached about the pressure used for the process? Why is this compromise needed?

4. What effect does the catalyst have on the size of the yield of ammonia?

5. What effect does the catalyst have on the speed that the yield of ammonia is obtained?

6. During the process, the reaction mixture is removed from the reactor, and cooled. The ammonia condenses to a liquid, and the unreacted nitrogen and hydrogen gases are recycled back into the reactor. Contrast the boiling point of ammonia with those of nitrogen and hydrogen.

Freddie09 · May 29, 2009

i need help with number 6 too

SoMeRaNdOm. · May 30, 2009

6. boiling point of ammonia is -33<meta http-equiv="Content-Type" content="text/html; charset=utf-8"><meta name="ProgId" content="Word.Document"><meta name="Generator" content="Microsoft Word 10"><meta name="Originator" content="Microsoft Word 10"><style>  </style>°C, nitrogen in -196<meta http-equiv="Content-Type" content="text/html; charset=utf-8"><meta name="ProgId" content="Word.Document"><meta name="Generator" content="Microsoft Word 10"><meta name="Originator" content="Microsoft Word 10"><link rel="File-List" href="file:///C:%5CDOCUME%7E1%5CTHEPRI%7E1%5CLOCALS%7E1%5CTemp%5Cmsohtml1%5C01%5Cclip_filelist.xml"><style>  </style>°C and hydrogen is -253<meta http-equiv="Content-Type" content="text/html; charset=utf-8"><meta name="ProgId" content="Word.Document"><meta name="Generator" content="Microsoft Word 10"><meta name="Originator" content="Microsoft Word 10"><link rel="File-List" href="file:///C:%5CDOCUME%7E1%5CTHEPRI%7E1%5CLOCALS%7E1%5CTemp%5Cmsohtml1%5C01%5Cclip_filelist.xml"><style>  </style>°C

rheyn · May 31, 2009

SoMeRaNdOm. said:
6. boiling point of ammonia is -33<META content=Word.Document name=ProgId><META content="Microsoft Word 10" name=Generator><META content="Microsoft Word 10" name=Originator><STYLE>  </STYLE>°C, nitrogen in -196<META content=Word.Document name=ProgId><META content="Microsoft Word 10" name=Generator><META content="Microsoft Word 10" name=Originator><LINK href="file:///C:%5CDOCUME%7E1%5CTHEPRI%7E1%5CLOCALS%7E1%5CTemp%5Cmsohtml1%5C01%5Cclip_filelist.xml" rel=File-List><STYLE>  </STYLE>°C and hydrogen is -253<META content=Word.Document name=ProgId><META content="Microsoft Word 10" name=Generator><META content="Microsoft Word 10" name=Originator><LINK href="file:///C:%5CDOCUME%7E1%5CTHEPRI%7E1%5CLOCALS%7E1%5CTemp%5Cmsohtml1%5C01%5Cclip_filelist.xml" rel=File-List><STYLE>  </STYLE>°C

It is also implied that you need to account for this difference in BP.

Reason for difference: Due to the very electronegative N atom and positive H atom, Ammonia (NH3) is able to form strong hydrogen bonds, dipole dipole forces and weak dispersion forces with other NH3 molecules thus giving it a higher boiling point than N2 and H2, which are only able to form weak dispersion forces.

clintmyster · May 31, 2009

2. What compromise is reached about the temperature used for the process? Why is this compromise needed?

A compromise must be achieved between temperature and equilibrium yield. By Le Chatelier's principle, an increase in temperature will favour the endothermic backwards reaction and less NH3 will be produced. An increase in temperature however means an increase in the rate of reaction due to more successful collisions (Kinetic theory) and thus the reaction reaches equilbirum more rapidly. Thus as a compromise, moderate temperatures of 400-500 oC is used.

3. What compromise is reached about the pressure used for the process? Why is this compromise needed?

An increase in pressure means more gas particles and hence more collisions (by Kinetic theory). On the negative side however, highly sophisticated equipment must be built to handle more extreme pressures. With high pressures, there is also the risk of explosions that could potentially be catastrophic. Thus a compromise is required so pressures are adequate to speed up a traditionally slow process but also to prevent explosions. Subsequently pressures of 250atm are used.

4. What effect does the catalyst have on the size of the yield of ammonia?

It has no effect on the yield of ammonia.

5. What effect does the catalyst have on the speed that the yield of ammonia is obtained?

A catalyst increases the rate of the forward and backwards reactions so equilibirum is reached more rapidly. It also lowers the activation energy but

Help on question about Haber Process (1 Viewer)

EViL.GENiUS

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Freddie09

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SoMeRaNdOm.

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rheyn

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clintmyster

Prophet 9 FTW

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