Question: You have a 4.5 kg lead block at room temperature.
Part A: Find the energy required to raise the lead’s temperature to its melting point.
Part B: Find the energy required to melt the lead once it’s reached the melting point.
I got the answer to part A. It is 1.8×10^5 J. But I can not find the answer to part B. Could you please help?
look up "heat of fusion" for lead
it's like the specific heat, but for melting
Sure, I can help you with part B of your question.
To find the energy required to melt the lead once it has reached its melting point, we need to use the concept of latent heat of fusion.
The latent heat of fusion (L) is the amount of heat energy required to change a substance from its solid state to its liquid state at a constant temperature. For lead, the latent heat of fusion is approximately 24,900 J/kg.
Given that the mass of the lead block is 4.5 kg, we can calculate the energy required to melt it using the formula:
Energy required to melt = Latent heat of fusion × Mass of the substance
Substituting the values, we have:
Energy required to melt = 24,900 J/kg × 4.5 kg
Calculating this, we get:
Energy required to melt = 112,050 J
Therefore, the energy required to melt the lead block once it has reached its melting point is approximately 112,050 J.
I hope this helps! Let me know if you have any further questions.