Respuesta :
The answer is 2.49 x 10^5 KJ. This was obtained (1) use the formula for specific heat to achieve Q or heat then (2) get the energy to melt the copper lastly (3) Subtract both work and the total energy required to completely melt the copper bar is achieved.
Answer:
2.42 x 10^8 J
Explanation:
m = 403 kg
T1 = 320 K
c = 386 J/Kg C
L = 205 kJ / kg = 205000 J/Kg
T2 = 1357 K
Heat used to increase the temperature till 1357 K
H1 = m x c x (T2 - T1)
H1 = 403 x 386 x ( 1357 - 320)
H1 = 1.6 x 10^8 J
Heat used to melt
H2 = m x L
H2 = 403 x 205000 = 8.2 x 10^7 J
Total heat used to melt completely
H = H1 + H2
H = 1.6 x 10^8 + 0.82 x 10^8 = 2.42 x 10^8 J
