In: Chemistry
A piece of iron (mass = 25.0g) at 95.0 C is placed in a styrofoam coffee cup containing 25.0 g of water at 25.0 C. If not heat is lost to the cup or surroundings, what will the final temperature of the water and iron be? The specific heat capacity of iron = 0.449 J/gC and water = 4.18 J/gC.
The heat lost by the iron should be the same as the heat absorbed by the water, as stated by the first law of thermodynamics, so we have:
Using the expression for calculating heat:
Where m is the mass of substance, C is its heat capacity and delta T is the change in temperature (T final - T initial), we get:
Notice that the final temperature will be the same for both, since they are in the same vessel. We can rearrange this to:
So we get: