How much amount of heat is required to convert 1 kg of ice at -10 degrees C into steam at 100 degrees C at normal pressure?

Specific heat of ice = #2100 J Kg^-1 K^-1#
Latent heat of fusion of ice = #3.36 * 10^5 J kg^-1#
Specific heat capacity of water = #4200 J kg^-1 K^-1#
Latent heat of vaporization of water = #2.25 * 10^6 J kg^-1#

1 Answer
Jan 2, 2018

3,027,000 J or 3,027 kJ

Explanation:

I studied this in chemistry although your process may be different.

Formulas used:

q=(mass)(specific heat capacity)(Final temp-Initial temp)
q=(mass)(latent heat)
H=sum up the amounts of q

*q represents heat and H represent enthalpy

First,

In order to find the total amount of heat we need to break it into steps , since water is in different states and temperatures.

We know the freezing and boiling points of water are 0 degrees Celsius and 100 degrees Celsius, respectively. Using this, we can separate the states;

   we start with ice (solid) and then water (liquid) and end with 
   steam (gas) so you can think of it as increasing in temperature

*one reason we don't go from solid to gas is because we aren't given latent heat of sublimation

Second,
So we know it goes from ice @ -10 degrees Celsius (or 263.15 K) to steam @ 100 degrees Celsius (or 373.15 K), and we know the freezing and boiling points of water and the formulas; we can now solve the problem!

we need to find the heat (q) needed to raise the temp of ice from -10 degress Celsius to 0 degrees celsius and so we use:

q=(mass)(specific heat capacity)(final temp-initial temp)
mass is 1 kg, specific heat is of ice, final temp is 0 but it is better to convert to Kelvin , and initial temp is -10 degrees Celsius
you get 21000 J

every time we need to find the heat to RAISE or LOWER the temperature we use this formula

Third,
Now that we have the ice in 0 degrees Celsius and we have calculated the amount of heat required to bring the ice to this temperature, we can now convert it to liquid using the other formula!

q=(mass)(latent heat of fusion)
you get 3.36 x 10^5 J

Fourth,
the rest is the same process until you get to steam at a temp of 100 degrees Celsius.

Tried to explain it the best I can.
Hope this helps!

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