I have been having a lot of trouble with this problem for Physics. I think that it deals with Latent Heat. Can someone explain to me how I do this? I'm so confused!
The problem:
How much energy is needed to melt .225kg of lead so that it can be used to make a lead sinker for fishing? The sample has an initial temperature of 27.3 degrees celcius. and is poured in the mold immediately after it has melted.
I'm not sure if this has anything to do with the problem, but If it helps I know that the specific head capacity of lead: 1.28X10^2 J/kg(degCelcius). I'm really confused, any help is appreciated!
2007-02-22 16:31:14 · 2 answers · asked by Blue 4 in Science & Mathematics ➔ Physics
Lead Specific Heat = 0.130 j/g/°C
Latent Heat = 22.4kJ/kg
Melting Point = 328°C
The lead is first heated from 27.3 to 328°C = ΔT = 300.7°
...Sensible heat = 300.7 x 0.13 x 0.225 = 8.796 kJ
The Lead is then melted:
*..Latent heat = 0.225 x 22.4 = 5.04 kJ
*...Total heat energy required = 8.795 + 5.04 = 13.835 kJ
2007-02-23 01:14:10 · answer #1 · answered by Norrie 7 · 0⤊ 0⤋
You also need the melting point of lead and the heat of fusion. The specific heat gets you the energy required to raise the lead to the melting point, but the heat of fusion is required to actually melt the lead.
http://en.wikipedia.org/wiki/Lead
2007-02-22 16:40:28 · answer #2 · answered by arbiter007 6 · 0⤊ 0⤋