Question

A 1.4 kg block of iron at 36 ∘C is rapidly heated by a torch such that 16 kJ is transferred to it. What temperature would the block of iron reach assuming the complete transfer of heat and no loss to the surroundings? If the same amount of heat was quickly transferred to a 830 g pellet of copper at 24 ∘C, what temperature would it reach before losing heat to the surroundings? qcs, Fe(s)cs, Cu(s)===mcsΔT0.450 J/g⋅∘C0.385 J/g⋅∘C Express the final temperatures of the iron and copper in ∘C to two significant figures separated by a comma.

Answer 1

A 1.4 kg block of iron at 36 ∘C is rapidly heated by a torch such that 16 kJ is transferred to it.

1KJ = 1000J , 1Kg = 1000g

Given : Cs, Fe(s)= 0.450 J/g*C
Cs, Cu(s)= 0.385 J/g*C

Fe ---- 16 KJ or 16000 J and 1.4 Kg or 1400 g of block of iron

Q = m * c * (delta T)

m = mass , c = Specific heat capacity , Q = heat transferred ,delta T = change in temperature

Fe ---- 16000 J = 1400g * (0.450J/g⋅^∘C) * ( T - 36^oC)
T - 36 = 25.3
T = 61.39 ^oC

If the same amount of heat was quickly transferred to a 830 g pellet of copper at 24 ^∘C

Q = m * c * (delta T)

m = mass , c = Specific heat capacity , Q = heat transferred ,delta T = change in temperature

Cu ---- 16000 J = 890g * (0.385J/g⋅^∘C) * ( T - 24^oC)
T - 24^oC= 46.69
T = 70.69 ^oC

The final temperatures of the iron and copper in 61^oC , 71 ^oC ( two significant figures separated by a comma)