Calorimetry

[Samira 2B]

In a calorimetry problem where ice with a temperature below 0 C is put into water and you are asked to find the final temperature, would you have to have 3 q's for ice: one for the change of heat for ice to 0, the H of fusion and then the change of heat from 0 to the final temperature? or would you just do one for the change of heat for ice to 0 and then H of fusion?

[Nehal Banik]

I feel like you would have to do 3, because the ice is changing from lets say -5 degrees celcius to 0 and then melting and then changing from 0 celcius to the final temperature of the water so I feel like you would have three q equations on one side and set that equal to negative of q of the water where you are also solving for the final temperature.

[Sally Nason - 1K]

Every time there is a temperature change or a phase change you need a separate equation. Usually when an ice cube has a phase change it first has to gain heat or lose heat to reach the right temperature for the phase change. That would be 2 equations. Then, if the ice cube changes temperature after the phase change you need a third equation.