How many BTUs are needed to heat one gallon of water to 200 degrees?

Assume the water is initially at 40 F and 14.7 psia.

m = ( 1.0 gal ) ( 1.0 ft^3 /7.4805 gal ) ( 62.43 lbm / ft^3 ) = 8.346 lbm

Q = Delta U = ( m ) ( Cv ) ( T2 - T1 )

Q = ( 8.346 lbm ) ( 1.00 Btu / lbm - Fdeg ) ( 200 F - 40 F ) = 1335 Btu <----------------

I depends of the starting temperature of the water.

A BTU is the amount of energy required to raise 1 pound of water 1 degree Fahrenheit ... water weighs about 8.34#/gal ... so 8.34 BTU's are required to raise 1 gallon of water 1 degree F. If your starting temperature of the water was 40 degrees F ... there would be 160 degree rise to 200 degrees or ...

1,334 BTU's are required to raise 1 gallon of water from 40 degrees to 200 degrees Fahrenheit

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