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When we're calculating questions involving solving for q (heat transfers), I'm a little bit confused on when we would use the specific heat of ice and when we would use the specific heat of water - for questions involving phase changes where ice melts.
You would use the specific heat of ice when it is in the ice phase. For example, say you want to find the q added to the system to get ice at -10 degrees celsius to water at +10 degrees celsius. You would find q needed to raise temperature from -10 to 0 degrees using specific heat of ice in the equation . Then find the q from the phase change from solid to liquid. And finally, add the q that you get from raising the temperature from 0 degrees to 10 degrees using the specific heat of water.
To determine which specific heat capacity to use, you need to look at the phase of the substance. More specifically, if you are working on a problem in which you are calculating the heat required to change ice at -10 degrees C to liquid water at 0 degrees C, you would first calculate the heat associated with the increase in temperature, using the specific heat capacity of ice. After, you would calculate the heat associated with the phase change using the enthalpy of fusion for water.
Water is only ice below 0 degrees, so we would use the specific heat of ice below that and then include the heat of fusion at 0 degrees then the specific heat of water above 0 degrees. So we use ice -> phase change -> water. Your delta temperature for the ice should have 0 as the final, and the delta temperature for water has 0 as initial, usually, if your total temperature range is negative->positive.
I get confused with this a lot to but you just have to know that under 0 degrees Celsius will be ice and above will be water and if its at 0 degrees it will usually tell you what current state its in
We would use specific heat of ice when H20 is presented in the problem as a solid and undergoing a fusion reaction in the reaction, and use specific heat of water when H20 is being presented in the problem as a liquid.
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