Lets say we have two 1 kg blocks of metal One is aluminum an

Let\'s say we have two 1 kg blocks of metal. One is aluminum and the other is iron. Initially, both blocks are at 25 degreeC. a. How much heat must be added to each block to raise each block\'s temperature to 350degreeC? b. If the two heated blocks are then placed in the same insulated container in which the blocks are in thermal communication with each other, what is the final temperature of each block after equilibrium is reached? List any assumptions you make for this simple analysis. c. Let\'s say that only the aluminum block has been heated to 350 degreeC while the iron block was kept at 25 degreeC. If these two blocks are then placed in the same insulated container in which the blocks are in thermal communication with each other, what is the final temperature of each block after equilibrium is reached? List any assumptions you make for this simple analysis.

Solution

a)Specific heat of Al and Fe 900 J/kg C and 450 J/kg C respectively.

heat to raise temp. of Al block=(350-25)(900)

=2.925X10⁵ J

raise temp of Iron block is

=1.4625X10⁵ J( specific heat of Iron is half of aluminum)

b) If the blocks are kept in an insulated container ,assuming heat is not lost to air in the container, both the blocks will be at 350 C^0.

^{c) aluminum block is heated to 350} C⁰  . Heat flows from Al to Fe. heat lost by Al is heat gained by Fe.

if t is the equilibrium temp.,

900X(350-t)=(t-25)X450

t=242 C⁰

d) heat flows from Fe to Al.

450X(350-t)=(t-25)X900

t=133 C⁰

In all cases it is assumed that heat is exchanged between the two blocks and there are no losses to air or container.