25.6 {\rm mL} of ethanol (density =0.789 {\rm g}/{\rm mL}) initially at 8.0^\circ {\rm C} is mixed with 39.5 {\rm mL} of water (density = 1.0 {\rm g}/{\rm mL}) initially at 23.1^\circ {\rm C} in an insulated beaker.

Question

Assuming that no heat is lost, what is the final temperature of the mixture?

Answer 1

[mass ethanol x specific heat ethanol x (Tfinal-Tinitial)] + [mass H2O x specific heat H2O x (Tfinal-Tinitial)] = 0
The only unknown is Tf. Solve for that.

Answer 2

so am I treating density as Sp. heat?

Answer 3

Of course not. Use density as in mass = volume x density to convert the volumes in the problem to grams. The specific heat is either given in the problem or it will be in your text/notes. I don't have specific heat tables memorized although I remember that H2O is 4.184 J/g*C or 1 cal/g*C. Use the one you are familiar with.