50g of water at 100 celsius is combined with 25g of water at 50 celsius. What is the final temperature of mix

Question

please show steps

i think you use q=mCp(deltaT)

Answer 1

first find the excess energy that the hotter one has because it is 50 degrees hotter than the colder one:

q = mCp(deltaT)

q = 50g ( 4.184 J/g-C)(50 C)

q = 10,460 joules of excess energy

now if both were at the colder temp, we would have 75 grams of water @ 50 Celsius,... & if we added that excess energy to them, they would rise to the same temp that they would have equilibrated at by themselves:

q = mCp(deltaT)

10,460 joules = 75g ( 4.184 J/g-C)(deltaT)

dT = 33.33 celsius would be the rise in temp above 50C

your answer is 83C