Molar Volumes of Solid and Liquid Lead at Normal Melting Temperature
What are the molar volumes of solid and liquid lead at the normal melting temperature?
Calculate the pressure using the given data.
Answer:
The molar volumes of solid and liquid lead at the normal melting temperature are, respectively, 18.92 cm3 and 19.47 cm3.
To calculate the pressure, we use the formula:
ΔP = (ΔH / ΔV) ln(T2 / T1)
where,
ΔH = change in enthalpy from solid to liquid = 4810 J/mol
ΔV = change in volume from solid to liquid = 0.55 cm3/mol
T2 = 620 K, T1 = 600 K
So,
ΔP = (4810 / 0.55) ln(620 / 600)
ΔP = 286.76 J/cm3
Converting to atm:
ΔP = 2830 atm
Explanation:
The molar volumes of solid and liquid lead at the normal melting temperature provide information on the volume occupied by a mole of lead in its solid and liquid states. The molar volume of solid lead is 18.92 cm3, while the molar volume of liquid lead is slightly larger at 19.47 cm3.
To calculate the pressure, the formula involving the change in enthalpy (ΔH), change in volume (ΔV), and temperature (T) differences between the solid and liquid states of lead is utilized. By substituting the values into the formula, the pressure change is determined to be 2830 atm.