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Be aware of the heat/temperature curve for water. A lot of the problems we have done have had ice at zero degrees so it will just start to melt when heat is added since zero is the melting point. If we start at less than zero degrees, say -3, then to get to the melting point we need to raise the temperature 3 degrees in which case we use q=mcdeltaT where C is the specific heat of ice because the H2O is in its solid state.
Yeah I always find it helpful to draw out the phase change diagram; if you start below 0 degrees celsius when you are still in the ice phase, then you need to use the specific heat capacity of ice. We generally use the specific heat capacity of water in our problems because we often deal with ice melting to water, where we often times are already at the freezing point of 0 so then the specific heat capacity of ice doesn't need to be taken into account.
Specific heat capacity of ice, 2.03 J/g*C, would be used when trying to find the heat needed to bring up the temperature of the ice before it melts. This specific heat capacity would be used in q=mCdeltaT which is a temperature change and not a phase change.
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