An aluminum spoon at 84 C is placed in a Styrofoam cup containing 0.180 kg of water at 12 C. If the final equilibrium temperature is 21 C and no heat is lost to the cup itself or the environment, what is the mass of the aluminum spoon?

Answer 1

Heat lost by spoon = heat gained by water
Use that heat, the aluminum temperature drop, and the specific heat of aluminum to get the mass.

Ignore the styrafoam mass. It acts as an insulator to keep the heat inside, and weighs very little.

Answer 2

So do I multiply all of the numbers (heat, temp. and specific heat) to get my mass? And for the temp. should I convert it to K? Or leave it to C?

Answer 3

0.98*0.18*21-84 = 21-12*4.186*Ms
11.1132 = 37.674Ms
Ms = 0.29 Kg

my answer wasn't right. what am i doing wrong?