November 30, 2021, 06:36:38 PM
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Topic: [itex]\Delta H^{\circ}_C[/itex] of pure acetylene in Oxyacetylene torch  (Read 636 times)

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Offline Win,odd Dhamnekar

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Standard enthalpy of combustion
(ΔH°c)) is the enthalpy change when 1 mole of a substance burns (combines vigorously with oxygen) under standard state conditions; it is sometimes called “heat of combustion." at 25°C and one ATM pressure. [itex]\Delta H^{\circ}_c[/itex] of Acetylene is -1301.1 kJ mol-1

  Although the gas used in an oxyacetylene torch (below Figure) is essentially pure acetylene, the heat produced by combustion of one mole of acetylene in such a torch is likely not equal to the enthalpy of combustion of acetylene mentioned above. Considering the the standard conditions for which above ΔH°c value of acetylene  are reported, suggest an explanation.

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Offline mjc123

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Well, what is the difference between standard conditions and conditions in a torch flame?

Offline Win,odd Dhamnekar

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Air-acetylene produces a flame temperature of around 4000° F (2200° C). This is hot enough to solder aluminum work glass, repair radiators and braze plumbing fixtures. It is not hot enough to weld steel. When acetylene is burned in pure oxygen, the flame temperature may be as high as 5730° F (3166° C).


The oxyacetylene process produces a high temperature flame over 3,000 degrees C, by combustion of pure oxygen and acetylene.
Any science consists of the following process.
 1) See 2) Hear 3) Smell if needed 4) Taste if needed
5) Think 6) Understand 7) Inference 8) take decision [Believe or disbelieve, useful or useless, healthy or unhealthy, cause or effect, favorable or unfavorable, practical or theoretical, practically possible or practically impossible, true or false or  any other required criteria]

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