A sample of substance X that has a mass of 326.0 g releases 4325.8 call when it freezes at its freezing point. If substance X has a molar mass of 58.45 g/mol, what is the molar heat of fusion for substance X

Answer : The molar heat of fusion for substance X is, 775.6 cal/mol

Explanation :

First we have to calculate the moles of substance X.

Given:

Molar mass of substance X = 58.45 g/mole

Mass of substance X = 326.0 g

Now put all the given values in the above expression, we get:

Now we have to calculate the molar heat of fusion for substance X.

where,

Q = heat releases = 4325.8 cal

= molar heat of fusion for substance X = ?

n = moles = 5.577 mol

Now put all the given values in the above expression, we get:

Thus, the molar heat of fusion for substance X is, 775.6 cal/mol

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sio2 (quartz)