how much heat must be added to 5.0 g of solid lead at 30 degrees celcius to convert it to liquid lead at the melting point?
Note the correct spelling of celsius.
The melting point of Pb is 327.5 C.
q added to raise temperature from 30 C to 327.5C is
q1 = mass Pb x specific heat Pb x delta T. You will need to look up the specific heat Pb. delta T is 327.5-30.
q2 = heat needed to melt Pb at 327.5 C is
q2 = mass Pb x heat fusion Pb.
You will need to look up the heat fusion.
Total q = q1 + q2.
thanks dr.bob
so is the answer 316 joules?
You didn't provide what you used for the melting point or the heat fusion or the specific heat so I don't know it that is right or not. Using 327.5 for m.p. and 22.4 J/g for heat fusion and 0.16 J/g*C, I obtained 350 Joules.
To calculate the amount of heat required to convert a solid to a liquid, we need to use the formula:
q = m * ΔHfus
where:
- q is the heat energy in joules (J)
- m is the mass of the substance in grams (g)
- ΔHfus is the molar heat of fusion in joules per gram (J/g)
First, we need to calculate the mass of solid lead in moles using its molar mass. The molar mass of lead (Pb) is approximately 207.2 g/mol. Therefore,
moles of Pb = mass of Pb / molar mass of Pb
= 5.0 g / 207.2 g/mol
Next, we need to determine the molar heat of fusion (ΔHfus) for lead. The molar heat of fusion represents the amount of energy required to convert one mole of a substance from solid to liquid at its melting point. For lead, ΔHfus is approximately 24.7 J/g.
Now, we can calculate the amount of heat energy required:
q = (moles of Pb) * (ΔHfus)
= (5.0 g / 207.2 g/mol) * (24.7 J/g)
By plugging in the values and performing the calculation, you can find the amount of heat required to convert 5.0 g of solid lead at 30 degrees Celsius to liquid lead at its melting point.