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It depends a little on what temperature it is to start with.
The heat capacity of water is 4.184 J g–1 K–1 (which in calories is equal to 1 cal g–1 K–1), which means that it takes a little more than 4 Joules to heat 1 gram of water 1 °C. That means if the water is at room temperature (25 °C) you have to raise the temperature by 75 °C to reach the boiling point.
So 1 lb of water is is 453.59 grams, so that gives 1898.5 Joules (1.898 kJ) or 7943.3 calories (7.943 kcal) to heat 1 pound of water 75°C.
But that's just to get it to the boiling point. You then need more energy to convert the liquid water at 100 °C into gaseous water at 100 °C, and for that you need something called the heat of vaporization. For water that is 2258 J g-1(or 539.7 cal g-1).
So, multiplying by 453.59 g/lb, we get 1,024,357 J lb-1 (or 1024 kJ/lb), or 244.83 kcal per lb.
So most of the energy goes into turning water at 100 °C into steam at 100 °C, and so the answer is approximately 1025 kJ per pound, or 250 kcal per pound.
What else can I help you with?
How much time does it take to boil saltwater or pure water?
That is entirely dependent on: 1. Your relation to sea level. 2. How much water you have. 3. How much salt is in the salt water. 4. What amount of heat you are using.
Can you boil water with candle?
Yes, you can boil water with a candle by placing a heatproof container of water over the candle's flame. It may take more time compared to using a stove, but it can be done in an emergency or when camping.
Does it take more heat to heat water or to boil water?
It takes more heat to boil water than to simply heat water. Unless the water is already at its boiling point.
Will it take longer to boil salt water than fresh water?
Yes, salt water will take longer to boil than fresh water because the presence of salt increases the boiling point of the water. This happens because the salt disrupts the process of water molecules turning into steam, requiring more energy to reach the boiling point.
How long does it take to boil 2 gallons of 70 degree fresh water with 12500 BTU at sea level?
A BTU is a unit of energy, and (assuming you mean degrees Fahrenheit) 12500 BTU is not enough energy to boil two gallons of water. Doesn't matter if you put it in within the space of a second, or spend an hour doing it. That's not enough energy.
How Much energy does it take to boil 100 ml?
The energy required to boil 100 ml of water at room temperature (20°C) to boiling point (100°C) is about 4200 joules. This is the amount of energy needed to raise the temperature of water by 1°C per gram.
Is boiling water endothermic or exthermix?
Boiling water is endothermic as the water needs to take in energy from its surrounding in order to boil.
Why putting less water in kettle will help use less energy?
because it takes less time for the water to boil. I f you put more water in the kettle it will take a longer time for it to boil which takes in more energy
How much salt do you put in to make the water boil faster?
Adding salt to water actually increases its boiling point, so it will take longer for saltwater to boil compared to plain water. It is not recommended to add salt solely to make the water boil faster.
Does salt water boil faster than plain?
Salt (or anything dissolved into water) will increase the boiling point of water. It will take longer to come to a boil. Salt reduces the vapor pressure of the water and so requires a higher energy level to boil.
If you wanted to take the salt out of water can't one place seawater into a vacuum chamber and boil off the water and expend less energy than just heating it?
in order to boil water you need to heat it, so its the same thing
Why does it a take a full kettle of water to boil longer than a half full kettle?
The more water in the kettle, the longer it will take to reach boiling point. This is why it is wasteful in energy to boil a full kettle if you only want to brew a small cup of tea.
How much time will take to boil a half filled salted water in a pot?
5-30 minutes
Does it it take more energy to heat the water to 100 degrees celsius or boil it?
If by "boil" you mean have it all evaporate, that takes MUCH more energy. For example, to increase the temperature of one gram of water from 20 to 100 degrees Celsius, you need 4.2 joules/gram/degree times 80 degrees = about 336 joules; then, to evaporate all the water, you need an additional 2257 joules.
Why does hot water take longer to boil than cold water?
Hot water takes longer to boil than cold water because hot water is already closer to its boiling point, so it requires more energy to reach the boiling point compared to cold water.
What change take place when water start to boil?
when a water starts to boil it evaporates in to gas from gas to liquid
Will a little pot or big pot boil first?
The deeper the water the longer it will take to boil. So if you put a small amount in a big pan it will boil much faster than a small amount in a small pan.
