Converting Btu to J: Troubleshooting Heat Capacity of Water

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SUMMARY

The discussion focuses on converting British thermal units (Btu) to joules (J) using the heat capacity of water. The correct formula for this conversion is Btu = C(water) * m(1 lb) * dt(1 F), where C(water) is 4.186 kJ/(kg*K) and m is the mass in kilograms. The error arises from the temperature conversion; 1 F should be converted using the factor of 5/9 to obtain the correct energy value. The accurate conversion yields 1 Btu = 1054 J, confirming the necessity of precise unit conversion in thermodynamic calculations.

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Homework Statement



I am just trying to convert Btu to J based on the heat capacity of water and it is not giving me the right answer.

Homework Equations





The Attempt at a Solution



Btu = C(water) * m(1 lb) * dt(1 F)

1 lb = 0.454 kg
1 F = 9/5 K

1 Btu = 4.186 kJ/(kg*K) * .454 kg * (9/5)K = 3.42 kJ < should be 1054 J, what am I doing wrong?
 
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Perhaps (5/9) ?
 
I thought 1 F = 9/5*C + 32?
 
You want the amount of energy to heat the water through 1 fahrenheit so it's c->f
 
I have the heat capacity of water in kJ/(kg*K) so arent I converting 1 fahrenheit degree to K?
 
You are calculating the energy needed to heat one pound of water through 1 f
So just like you have the amount of kg in a lb (0.454) you also need the amount of c in an 'f' ie 5/9
 

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