Calculating Final Temperature

[Reynaldo Fernandez 3L]

What's the best way to calculate the final temperature of a mixture when given just the initial temperature of each of the two mixtures?

[Chem_Mod]

Hi Reynaldo,

It really depends on the question and what values you are given. If you are given the masses/moles, specific heat capacities, and initial temperatures of two substances, and there is no heat lost to the surroundings, you can equate the two thermochemistry equations each other, such that:

q(sub1) = mc∆T = q(sub2) = mc∆T

Be careful of where you are plugging in values (e.g., substitute the initial temperature into the side with the respective mass). Also note any phase transitions (e.g., final temperature of ice and water where you are left with no ice at the end such that the ice has gone through a phase transition from solid to liquid).

I like to rearrange the equation so that I have the final temperature on one side and everything else on the other side, so that way when I'm checking my answer (like on an exam), I can check that I have the correct set-up before checking my calculations.

Hope that helps!