Answer the question.

Discussion in 'Chemistry' started by Beaconator, Jun 2, 2014.

  1. Motor Daddy Valued Senior Member

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    5,425
    It's only 11PM, who cares?? Not me. I only wanted to know how much energy a 100 Watt light bulb consumed for 10 hours.

    Why would I want to talk about your next measure of energy (power*time)???
     
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  3. billvon Valued Senior Member

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    Then why did you ask about it?
     
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  5. Motor Daddy Valued Senior Member

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    Because people are saying a gallon of gas has energy while it's in the can, albeit spread out and not available.
     
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  7. Motor Daddy Valued Senior Member

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    I simply asked how much energy is in the gas, and how much is it spread out?

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    How many kw-hrs are in a gallon of gas, and how is it distributed?
     
  8. billvon Valued Senior Member

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    So you asked about it because someone said something you disagreed with, but you aren't asking about it because you don't care.

    Your train of thought is as clear as your grasp of physics.
     
  9. Motor Daddy Valued Senior Member

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    Maybe if you would have followed along and understood what was happening in this thread you would understand it a little better? You don't seem to know what's up.

    People made statements and I am asking them to quantify their statements. No such luck, they don't care to do that. They just want to talk about little green monsters that you can't measure or see.
     
  10. billvon Valued Senior Member

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    You'll have to take that up with this guy MotorDaddy. He keeps saying he doesn't care about those statements.

    (From this point on I will refer to the "I'm just asking questions here" Motordaddy as MDQ and the "I don't care; I'm not asking anything" Motordaddy as MDT.)
     
  11. Motor Daddy Valued Senior Member

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    5,425
    So billvon, how many kw-hr is in a gallon of gas, and how are those kw-hr distributed in the gas?
     
  12. exchemist Valued Senior Member

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    12,451
    Well, if you read my reply carefully you'll see I qualify "not available" with the caveat that that depends on whether you have a lower temperature heat sink available. (I have to cover the options because I know what a nitpicking and deliberately obtuse git you can be.)

    The energy in an unburnt gallon of gas is not in the form of heat, so it is, of course, available. Once the gasoline has been burnt and is thereby turned to high temperature heat, some of it is available to do work pushing the pistons of your car, but this lowers its temperature, at which point the heat then comes out (of the exhaust and via the radiator), into the atmosphere as low temperature waste heat. At this point it is unavailable.

    Got it?
     
  13. billvon Valued Senior Member

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    MDQ, a gallon of gas at room temperature contains ~.5 kilowatt-hours of thermal energy. In a well mixed liquid it is distributed throughout the gallon.
     
  14. Motor Daddy Valued Senior Member

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    5,425
    Read my lips: Energy=Power*Time
     
  15. Motor Daddy Valued Senior Member

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    5,425
    So the gas gets hotter, and the can heats up and melts, right? How did you measure the .5 kw-hr of thermal energy? How much time elapsed? How much does the temperature of the gas rise in 1 hour?
     
  16. billvon Valued Senior Member

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    To MDQ:
    No. A kilowatt-hour is a unit of ENERGY not a unit of POWER. Thus things don't continue to get hotter just because they have energy.
    293 degrees K. 2.2 kilograms of gasoline. Look up the thermal constant of gasoline and calculate it for yourself.
    See above.
     
  17. Motor Daddy Valued Senior Member

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    5,425
    Where did I say a kw-hr is a unit of power???

    So no getting hotter, so no thermal energy. So where is the energy in the gas? How much work is the gas doing in the can?

    A kilowatt-hour is a unit of energy which is equal to power*time, which is equal to (work/time)*time, which is equal to ((force*distance)/time)*time. So energy= ((force*distance)/time)*time

    Good now?

    Do you need me to break it down in torque, RPM, and time, for you?

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  18. billvon Valued Senior Member

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    Here: "So the gas gets hotter, and the can heats up and melts, right?"
    I see you do not understand the term "thermal energy."
     
  19. Motor Daddy Valued Senior Member

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    5,425
    The problem is not me, it's your failure to understand what a unit of energy is. If you claim the gas has thermal energy of .5 kw-hr, then how did you measure that while the gas was in the can?

    Please don't try to say you would take the gas and burn it, or that we know that gas can burn and can perform work in the future. Just tell me how you measured the thermal energy while the gas was in the can?
     
  20. billvon Valued Senior Member

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    I didn't measure it; I did the math. You can too. (Well, that might be a bad assumption. Trust me, it's easy to do.)
    No, you didn't mention anything about oxygen so the only available energy is the thermal energy inherent in the warm gasoline.
    Again, math.
     
  21. Motor Daddy Valued Senior Member

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    5,425
    I measured the energy of 1 kw-hr when the light bulb operated for 10 hours. In 10 hours of measure the bulb consumed 1 kw-hr of energy.

    How many kw-hr of energy did you measure in the gas when you measured the thermal energy, and how many hours did you measure, and perform your calculations with?
     
  22. origin Heading towards oblivion Valued Senior Member

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    11,888
    This is just another example of how your limited understanding of simple physics concepts leads to your meltdowns when someone tries to expand the concept beyond your tiny sliver of undertanding
     
  23. billvon Valued Senior Member

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    None. You do not need to know time to calculate energy. You are confusing power and energy again.
     

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