Oxygen difluoride is a colorless, very poisonous gas that reacts rapidly with water vapor to produce O2 and HF and heat:
OF2+H2O->O2+HF2 (DELTA)H=-318kJ
What is the change in internal energy for the reaction of 1 mol OF2?
I know I need to use P(DELTA)V=(DELTA)nRT but the temperature is not given. What do I do?
Enthalpy
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Re: Enthalpy
Since no temperature is given, assume standard conditions. The standard condition for temperature is 298K or 25ºC.
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Re: Enthalpy
The temperature should be in Kelvin because for the P(DELTA)V=(DELTA)nRT equation, the units of R is in J/mol*K !
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Re: Enthalpy
How do you know when to use Kelvin or Celsius in a problem? Can you just always use and convert a question to Kelvin?
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Re: Enthalpy
EmilyLeibovitch2E wrote:How do you know when to use Kelvin or Celsius in a problem? Can you just always use and convert a question to Kelvin?
How you know which unit to use is really dependent on the rest of the values in your problem and their units. Use the other values and units as a guide to help you determine whether to use K or C based on the formulas and given constants
Re: Enthalpy
I believe Kelvin is the ideal temperature to be used throughout this problem, although if information and a formula is specified in Celsius, then you most certainly can maintain the units in Celsius. Whichever you use, I believe I've heard my TA say that the key thing is to be consistent throughout a problem.
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Re: Enthalpy
Depending on the problem, it would most likely be in Kelvin. However, you should list out all the units of each value and then eliminate the overlapping units. For example, because the heat capacities have something to do with Celsius then in this case, you should use Celsius.
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Re: Enthalpy
For temperature, it will most likely be K.
However, either is fine if unit is specified in the answer.
However, either is fine if unit is specified in the answer.
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