Answer:
438 J/kg/°C
Step-by-step explanation:
Heat lost by iron = heat absorbed by water/copper
-m₁C₁ΔT₁ = m₂C₂ΔT₂ + m₃C₃ΔT₃
-(2 kg) C (30°C − 80°C) = (1 kg) (4186 J/kg/°C) (30°C − 20°C) + (0.5 kg) (385 J/kg/°C) (30°C − 20°C)
(100 kg°C) C = 41860 J + 1925 J
C = 438 J/kg/°C