How Can I Convert BTUs to Calories?

[Eclair_de_XII]

Homework Statement

"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.

Homework 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"

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)?

 

[Borek]

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

 

[SteamKing]

Homework Statement

"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.

Homework 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"

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)?

If 1 calorie = 4.184 J, and 1 BTU = 1054 J, why are you fiddling around with these other extraneous calculations?

 

[Borek]

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