A copper block of volume 1 L is heat treated at 500°C and now cooled by immersion in a 200 L light oil bath initially at 20 °C. Assuming no heat transfer with the surroundings, determine the final equilibrium temperature of the copper-oil system assuming the specific heat capacities of both are constant.

Respuesta :

Answer:

[tex]T_2=24.98^oC[/tex]

The  final equilibrium temperature of the copper-oil system is 24.98 degree Celsius

Explanation:

Assumptions:

No heat Transfer to surroundings=Q=0

No work done=W=0

Specific heat capacity of copper at constant volume=[tex]C_v=0.386\ KJ/Kg.K[/tex]

Specific heat capacity of light oil at constant volume=[tex]C_v[/tex]=[tex]1.8\ KJ/kg.K[/tex]

Density of copper=[tex]\rho_c=8900Kg/m^3[/tex]

Density of light oil=[tex]\rho_o=910\ Kg/m^3[/tex]

1 L=0.001 m^3,        200 L=0.2 m^3

Mass of copper=[tex]m_c=\rho*v[/tex]=[tex]8900*0.001=8.9\ Kg[/tex]

Mass of light oil=[tex]m_o=\rho_o*v_o=910*0.2=182\ Kg[/tex]

According to first Law:

Q-W=ΔU

According to assumptions:

ΔU=0

[tex]m_cC_v_(T_2-T_1_c)+m_oC_v(T_2-T_1_o)[/tex]=0

[tex]8.9*0.386(T_2-500)+182*1.8(T_2-20)=0\\T_2=24.98^oC[/tex]

The  final equilibrium temperature of the copper-oil system is 24.98 degree Celsius