Tungsten has been used to make light bulb filaments since 1908. The melting point of tungsten is 3422C and the heat of fusion is 35 kJ/mole. Calculate the entropy change associated with the melting of one mole of tungsten.
Divide the heat of fusion by the Kelvin temperature of the melting point. That will be the entropy change. Make sure you convert 3422 C to Kelvin.
Thank you. I was missing the units the whole time.
S = H/T
Convert kj to Joules; convert C to K.
Entropy is sometimes stated in kJ/mole K, but you are right, kcal/mole K is more common
To calculate the entropy change associated with the melting of one mole of tungsten, we need to use the equation:
ΔS = ΔHfus / T
where ΔS is the entropy change, ΔHfus is the heat of fusion, and T is the melting point in Kelvin.
First, let's convert the melting point from Celsius to Kelvin:
Melting point in Kelvin = melting point in Celsius + 273.15
= 3422 + 273.15
= 3695.15 K
Now we can substitute the values into the equation:
ΔS = (35 kJ/mole) / (3695.15 K)
To convert kJ to J, we need to multiply by 1000:
ΔS = (35 kJ/mole) * (1000 J/kJ) / (3695.15 K)
ΔS = 9.47 J/K
Therefore, the entropy change associated with the melting of one mole of tungsten is approximately 9.47 J/K.