Question

A 4.21 kg lead billet is to be melted for a casting operation. Lead has a melting point of 328°C, a specific heat capacity of 128 J/(kg·°C), and a latent heat of fusion of 23,200 J/kg. (use correct number of significant figures in your final answer.)

(a) Calculate the amount of heat required to heat the lead from a starting temperature of 21.7°C to its melting point of 328°C.

(b) Calculate the amount of heat needed to melt the lead brick once it reaches 328°C.

Answer #1

A 2.03-g lead bullet traveling at 508 m/s strikes a target,
converting its kinetic energy into thermal energy. Its initial
temperature is 40.0°C. The specific heat is 128 J/(kg · °C), latent
heat of fusion is 24.5 kJ/kg, and the melting point of lead is
327°C.
(a) Find the available kinetic energy of the bullet.
J
(b) Find the heat required to melt the bullet.
J

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A home melting pot is used for a metal casting hobby. At the end
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atm: Melting point = 328°C Specific heat liquid = 0.138 J/g ⋅ °C
Specific heat solid = 0.130 J/g ⋅ °C Heat of fusion = 23.0 J/g
__J

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Estimate the speed that a lead bullet must have in order that it
melts completely when it strikes a target. Assume that all the
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A lead bullet of unknown mass leaves a rifle at a temperature of
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melting temperature of LEAd: 327 C specific heat of Lead: 0.13E3
J/(Kg.K) Latent heat of fusion: 22.9E3 J/kg

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