Question

A system consists of a sealed copper tank whose mass is 20kg, which contains 5 kg of liquid water, and an electrical register (negligible mass). The system is insulated on its outer surface. Initially, the temperature of the copper is 27˚C and the temperature of the water is 50˚C. The electric resister transfers 100 kJ of energy to the system. Eventually the system comes to equilibrium.

a) Sketch the system. Clearly label all components and include arrows indicating work or heat transfer processes.

b) Determine the final equilibrium temperature, in ˚C.

Answer 1

from Data Book Given Date : Mars of Cu Tanie = 20 kg Mais of water in it = 5kg ( specific heat) Gee = 0.385 ks/19k (specific hear) C weder = 4.187 Icslige Ti (Cu) = 27°C @ 300 k Ti (water) = joc ☺ 323k Electrical crosse = 100kg Trongfer To system = 2 Insulated from Outside Solº:- Lii - 1005 Electrical lus Thermor dmarie Scanned with CamScanner en

According to first law of Thermodynamic for a process: ISO = du + St / S8 = (Ug-()+dh where, so = Heat Interaction et system & scnounding. U = Total Internal Energy of 1 System (et water) after Praca le = Total Internal Energy of - System (het water) Before Process sw = work Interaction Bet System and Surrounding CS - =Scarleted with assume It is the final temb of both Cu & water o cooperanteaching Equillibrium State

SQzo ( since Insulated from outside) Ug = (y cu + (la) water = (mCT u + (mcTf) weser ={(Mc) out (MC) water} TJ (1. u, = (u) cu Hur) water If cu = If wester) I water CS Scanned with me Ti) cu +(MCT), Cangiganter -100 ks

=) Put abore Value in gut law Eq" for Process : 0 = {(mc leu + (Chater} } - {{ mC Til au foc i weser} 100 0 = {(2010:385) +(5x 4.184) } - {(2080*385 x 300) + ( 5* Y'187 X 323) } – loo 0 = 28.635 T - 9072.005 -100 Ti = 320.30.7 k 47.3°C] Reach Conclusion :- To Become the system in Equillibum State Net Heat will transfer from Weeter to Copper Even though there i t Electrical work transfer to the System. (Note : No Heat transfer takes place bet system and Sonounding rather It takes place within the System Calies chener au & Water.) Sccune oan & Water.)