A well-insulated copper tank of mass 13 kg contains 4 kg of liquid water. Initially, the temperature of the copper is 27°C and the temperature of the water is 50°C. An electrical resistor of negligible mass transfers 100 kJ of energy to the contents of the tank. The tank and its contents come to equilibrium.

Respuesta :

Answer:49.3

Explanation:

Given

mass of water [tex]m_w=4 kg[/tex]

mass of tank [tex]m_T=13 kg[/tex]

initial of temperature of water =[tex]50^{\circ}C[/tex]

initial of temperature of tank=[tex]27^{\circ}C[/tex]

Specific heat of water =4.184kJ/kg k

Specific heat of copper=0.386 KJ/kg k

From first law of thermodynamics we have

[tex]Q=\Delta U+W[/tex]

Given tank is insulated thus Q=0

[tex]-W=\Delta U[/tex]

work will be negative as it is being done on system

[tex]-\left ( -100\right )=\Delta U_{water}+\Delta U_{tank}[/tex]

[tex]-\left ( -100\right )=m_w\times c_{water}\left ( T-50\right )+m_Tc_{tank}\left ( T-27\right )[/tex]

[tex]100=4\times 4.184\left ( T-50\right )+13\times 0.386\left ( T-27\right )[/tex]

[tex]T=49.3^{\circ} C[/tex]