Depends on the temperature of the water.
If it is 32 degree water and you want 32 degree ice then you need a -144 BTU loss to change state from liquid to solid.
It takes 1 BTU to raise the temperature of 1 pound of water 1 degree (F).
If the water is 82 degrees then you would need a -50 BTU loss (+) 144 BTU to change state.
TOTAL WEIGHT OF WATER (X) 1 BTU (X) Degrees desired of change.
If it is ICE to WATER then it is the TEMP of ICE (X) .5 BTU (X) NUMBER OF DEGREES INCREASED = TOTAL BTU needs.
If you change state in the process you have to add 144 BTU for 32 degree ICE to 32 degree WATER and 970 BTU for 212 degree WATER to 212 degree STEAM but only when you change state.
Assuming the water is already at freezing temperature, and we need only convert its state from a liquid to a solid:
Therefore, it takes 143 BTUs to freeze one pound of water.
Approximately 8000 BTU.
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144 btu
46
32
144
This question is a little confusing in that BTUs are not generated in raising the temperature of anything; the input of heat is required. And if the questioner meant required instead of generated, then the question is still unanswerable as the amount of water must be specified, AND the starting temperature must be specified.
That depends on how much water you have, and what temperature it's starting at.If you have one pound of water, and its temperature is 40° F, then it will cool to 39° Fif you pull exactly one BTU of heat out of it.Different amounts of water, or different starting temperature . . . different amounts of heat.
The temperature of an object is directly proportional to the amount of heat energy it contains. And changing the temperature of an object, therefore, means changing the heat energy it contains. But the temperature is also dependant on the object's mass, and a property of the material called the specific heat. Specific heat is the the heat per unit mass that corresponds to a unit temperature (e.g. 1 degree) for the particular material. For example, liquid water's specific heat is 1 calorie per gram per degree celcius, or 1 cal/g∙°C. More about water: - For every 0.57 btu's* heat added to one pound of ice will raise the temperature of the ice 1°F at atmospheric pressure, up to 32°F. - For every 144 btus added to ice at 32°F and 1 atmosphere, one pound of ice will melt with no change in temperature. - For every btu of heat added to 1 pound of water the temperature will rise 1°F at atmospheric pressure, from 32°F to 212°F - For every 972.3 btus of heat added to water at 212°F and atmospheric pressure, 1 pound of water will be evaporated. - For every 0.47 btus of heat added to 1 pound of steam at atmospheric pressure the temperature will rise 1°F. * For metric units: 1 gram = 0.00220462 pounds, 252 calories = 1 btu, and 1°C = 1.8°F, with temperature of fusion at 0°C and temperature of evaporation at 100°C More generally, if we consider Q as heat energy in an object, then ΔQ is a change in that energy, and take the mass of a substance as m and the specific heat (at constant volume) as Cv and t2 and t1 are final and initial temperatures, then we get the following equation:- ΔQ=m∙Cv∙(t2-t1)
That depends on what the starting temperature of the water is,and what temperature you want it to reach.If you expect to get a number, you must first give the necessary numbers.
10.28
One BTU is the energy required to raise one pound of water by one degrees. Therefore, your answer would be one half.
6,520 Btus
A 100 pound propane tank has a capacity of 2,160,509 BTUs
1)This is a 5 part question. The first is realizing that 20F to 32F uses .5BTU per pound per degree. That means it takes 32-20=12*.5=6BTUs to get the ice to 32F. 2)Then you need to know the Latent Heat of Fusion for Ice which is 144BTUs (given). Lets assumes the ice changes from ice to water instantaneously at 32F. 3)Next we calculate the BTUs from 32F to 212F. Which is 1BTU per pound per degree F. 212-32=180 so it take 180BTUS. 4)Next we have to use the Latent Heat of Vaporization of water which will say instantaneously converts water to vapor. This takes 970BTUS (given). 5)Then we calculate the BTUS from 212F to 220F. Which is .5BTUs per pound per degree F which is 220-212=8*.5=4BTUs...... Finally add up all the BTUs and you get 6+144+180+970+4=1304BTUs.
BTUs to Evaporate One Pound of WaterQuick Answer: Somewhere around 1000BTU/lb Long answer: It depends on the temperature of the water you start with. Before you can evaporate the water, you must heat it to it's boiling point. The warmer the water you start with the fewer BTUs will be needed to heat the water to its boiling point. Keep in mind the BTUs require to raise the water to its boiling point are very few compared to the BTUs required to change the water from a liquid to a gas.One pound of steam contains 1150 BTUs. This is the energy you need to put into the water for it to evaporate if you start with water at 32F. If you start with water at 100F the water already has 70 BTU/lb so the BTUs required to evaporate the water when you start at 100F is 1150-70 = 1080 BTU and so on.You can get all this information in a steam table which can be found easily by searching the web.
There are no BTUs in an office water-cooler. But you can calculate how many BTUs are removed by the cooler. One BTU or British Thermal Unit is the amount of heat energy required to raise the temperature of one pound of water one degree Fahrenheit. There for when you remove one BTU you are lowering one pound of water one degree Fahrenheit. So if you know how many pounds of water you have and the temperature of the water you start with and the temperature of the water comming out of the cooler you can calculate how many BTUs the cooling unit of the water cooler has removed. BTU=Temp1 - Temp 2 X LB water
144
20,141 BTUs in one pound of natty.
Heat. Ice, solid water, at 32 degrees F needs 144 btus of heat per pound to liquify completely. Water at 212F needs 970.3 btus per pound to evaporate completely into dry steam. Water vapor (visible steam), in air, {say from a pot} is actually about 3 to 10% dry steam and only required about 28 to 100 btus per pound to vaporize and become airborne, This is an odd characteristic of water, that varying proportions of dry steam will carry large amounts of liquid water along with it as it evaporates (Wet Steam).Water can exist in all three states at the same time, in the same general vicinity. Ice floats on liquid water and the air around it will also contain some amount of water vapor (humidity).
From high school science class; it takes 144 BTUs to melt a pound of ice. That takes it to 32 degrees F. To then raise the temp to 72 deg., would take about 40 more BTUs.
20141 btus
212 - 80 = 132 degrees temperature increase x 1 pound water = 132 BTU