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How do I convert BTUs to calories?

  1. Mar 2, 2015 #1
    1. The problem statement, all variables and given/known data
    "The use of the British thermal unit (Btu) is common in much engineering work. A Btu is the amount of heat required to raise the temperature of 1 lb of water by 1°F. Calculate the number of joules in a Btu.

    2. Relevant equations
    "A calorie was originally defined as the amount of energy required to raise the temperature of 1 g of water from 14.5°C to 15.5°C. A calorie is now defined in terms of the joule:

    1 calorie = 4.184 J"

    3. The attempt at a solution
    I know one BTU is 1054 J. Here is what I believe to be correct:
    1-lb(453.59 g/lb)(4.148-J/1°C)(5/9°F/1°C) = 1054 J
    However, I'm a bit worried about my last factor. Isn't it supposed to be (5/9(°F - 32°)/1°C)?
     
  2. jcsd
  3. Mar 2, 2015 #2

    Borek

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    Staff: Mentor

    No. You are that there are 9/5 Fahrenheit degrees per °C, and you are not interested in where the scale starts.
     
  4. Mar 2, 2015 #3

    SteamKing

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    Staff Emeritus
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    Homework Helper

    If 1 calorie = 4.184 J, and 1 BTU = 1054 J, why are you fiddling around with these other extraneous calculations?
     
  5. Mar 3, 2015 #4

    Borek

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    Staff: Mentor

    My understanding is that he has to convert using only the data given.
     
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