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### Author Topic: How much steam from 500 calories of heat added to 2 litres of water?  (Read 3199 times)

#### xam

• Guest
##### How much steam from 500 calories of heat added to 2 litres of water?
« on: 15/10/2011 19:01:02 »

If five hundred kcal of heat is added to 2kg of water at 80°C, how much steam is produced?

What do you think?
« Last Edit: 15/10/2011 19:01:02 by _system »

#### CliffordK

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##### How much steam from 500 calories of heat added to 2 litres of water?
« Reply #1 on: 15/10/2011 19:28:30 »
Is this a math and science homework problem?

Typically I start by converting everything to grams and calories.
1000 calories = 1 kCal.
1000 grams = 1 kg.

1 calorie will raise 1 gram of water 1°C.
However, it takes 79.72 calories to vaporize one gram of water at 100°C.

So, what you basically do is calculate the number of calories to raise the water from 80°C up to 100°C

Subtract that from your total amount of energy, and that gives you the energy left to vaporize the water.  If it is negative, then you would not get any steam, and you could calculate the final temperature.

Assuming you still have some energy left over, you simply divide the the remaining energy at 100°C by 79.72 calories/gram to get the number of grams of steam vaporized.

#### Geezer

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##### How much steam from 500 calories of heat added to 2 litres of water?
« Reply #2 on: 15/10/2011 20:00:42 »
I'll give you a hint - less than half of it.

#### The Naked Scientists Forum

##### How much steam from 500 calories of heat added to 2 litres of water?
« Reply #2 on: 15/10/2011 20:00:42 »