Question

If you have 320.0 mL of water at 25.00 °C and add 110.0 mL of water at 95.00 °C, what is the final temperature of the mixture? Use 1.00 g/mL as the density of water.

Answer 1

Because you're just mixing water, the specific heat is the same for both liquids. So, it's just like adding a bunch of weighted numbers:

(320*25 + 110*95)/(320+110) = 42.91°C

You can use a fancy formula incorporating the specific heats, but they all cancel out in the end, since they're the same.

As a ballpark check, the average of 25 and 95 is 60°C, but you have more cool water than hot, so the result will be below the average.

Answer 2

Here's a little variation of this one:
"If you combine 310.0 mL of water at 25.00 °C and 100.0 mL of water at 95.00 °C, what is the final temperature of the mixture? Use 1.00 g/mL as the density of water."

ANS: 42.07 Degrees

Answer 3

If you combine 310.0 mL of water at 25.00 °C and 140.0 mL of water at 95.00 °C, what is the final temperature of the mixture? Use 1.00 g/mL as the density of water.

Answer 4

Steve is right