How much energy is needed to melt 15 grams of ice to water at #0^.C# ?
In Physics, when talking about energy in thermodynamics, we talk about heat.
Heat can be defined with the letter Q.
Specific heat is defined as the amount of heat that is needed to raise a 1kg mass by 1ºC/1K. Units
Liquid water has a very high Specific Heat Capacity. It is about 4180
To solve your problem, we will have to introduce a new concept, phase change . This happens when a substance goes through a change in state, in other words, it changes from liquid to solid , liquid to gas or gas to solid.
In your case, we are melting ice, which means the phase change will go from solid to liquid.
To calculate this you need a new concept, Specific Latent Heat (denoted with the letter L), which is the amount of heat that has to be supplied to a mass to change its phase. This can be calculated by:
To solve your problem, we will have to break it into parts:
- Heat needed to melt ice at 15ºC to 0ºC (still in solid state)
- Heat needed to melt solid ice at 0ºC to 0ºC liquid.
Before we start:
- Specific Heat of Ice (C)= 2108 J/(kg*ºC)
- Latent Heat of Ice (L) = 333*10^3 J/kg
This means that to melt a 0.015kg ice cube to water at 0ºC you will need 4520.7 J of heat.