Question

in one box of nails, there are 75 iron nails weighing 0.242 lb. the density of iron is 7.68 g/cm^3 . The specific heat of iron is 0.452 J/g C. The melting point of iron is 1535 C. How much heat in joules, must be added to the nails in the box to raise their temperature form 16 degrees C to 135 degrees C.

Answer 1

$0.242lb=0.242\times453.6=114.3g$

The number of nails in the box, the density of iron, as well as the melting point are not needed to solve this problem.

$Q=cm\Delta{T}=0.452J/g\degree{C}\times114.3g\times(135\degree{C}-16\degree{C})=6.15\cdot10^3J$

Answer: $6.15\cdot10^3J$