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One piece of copper at 105 degrees Celsius has exactly twice the mass of another

ID: 508687 • Letter: O

Question

One piece of copper at 105 degrees Celsius has exactly twice the mass of another piece, which is at 45 degrees Celsius. Both pieces are placed inside a calorimeter whose heat capacity is negligible. What is the final temp inside the calorimeter? (C or copper= 0.387 K/g.k )? One piece of copper at 105 degrees Celsius has exactly twice the mass of another piece, which is at 45 degrees Celsius. Both pieces are placed inside a calorimeter whose heat capacity is negligible. What is the final temp inside the calorimeter? (C or copper= 0.387 K/g.k )?

Explanation / Answer

We have two pieces of copper , one is at 105 o C and the other at 45 o C.

let Tf be the final temperature they reach.

Let the mass of the copper at 45 o C is X , then the mass of the copper at 105 o C will be 2X

Heat lost by copper at 105 o C = Heat lost by copper at 45 o C

                       m1C( 105 o c - Tf ) = m2 C (Tf - 45 o c)

                        2X ( 105 o c - Tf ) = X (Tf - 45 o c)[ specific on both sides get cancelled as both are copper]

                                 210oc - 2Tf = Tf - 45oc

                                             3Tf = 255oc

                                             Tf = 85oC

The final temperature will be 85oC