An unknown substance has a mass of 17.5 g. The temperature of the substance increases by 19.1 ∘C when 78.5 J of heat is added to the substance. What is the most likely identity of the substance?

Answer 1

Find the specific heat of the substance and then compare it to known substances. This question is impossible to answer because there are so many materials with the same values of C. Unless you are told more about the unknown (metal, non metal, element, compound, etc.) you can never identify it.

q = mC∆T

q = heat =78.5 J

m = mass = 17.5 g

C = specific heat = ?

∆T = change in temperature =19.1 degrees

Solving for C, we have

C = 78.5 J/(17.5 g)(19.1 degrees) = 0.2349 J/gº

Looks like a metal so look up specific heats of metals but it could be something else. No way to tell.