Question

what happens when two mixtures with different temperatures are mixed?

Answer 1

The first law of Thermodynamics applies to this system: delta U = Q -W.

Since there is no heat added, Q = 0. Since there is no work done, W=0.

Therefore, delta U = 0.

Now, look up u for liquid 1 at temperature 1 and multiply by the mass of liquid 1 to get U1a. Do the same for liquid 2 (using temperature 2 and mass of liquid 2) to get U2a. U1a+U2a = U

U is also equal to U1b+U2b where the b’s are the internal energies of the two liquids at the final temperature.

I used to know how to calculate directly from this point, but I’ve been out of school a long time. Since the warmer liquid must donate energy to the cooler liquid, you can estimate the final temperature using delta T * Cp1*m1 /(Cp2 * m2), where delta T is the original temperature difference between the liquids and the Cps are the heat capacities. Add the result to the cooler temperature and then look up the u’s and see if it works out. If not, try subtracting the result from the warmer temperature and do the same.

MARK BRAINLIEST.