Question

Calculate the heat required to melt 25.7 g of solid methanol at its melting point

Answer 1

Answer:

the heat required to melt the compound is 2.56k

Answer 2

The heat required to melt the compound is 2.56kJ.

Why?

To calculate the heat required to melt 25.7 g of solid methanol, we need to calculate its molar mass, know its chemical formula, its molar heat of fusion, and calculate how many moles represent 25.7g of the same compound.

Then, we need to use the following formula to calculate the heat:

$Q=N*u$

Where,

N is the moles of the compound

u, is the molar heat of fusion of the compound (J/mol)

We know that the molar mass of methanol is :

$32.042\frac{g}{mol}$

So, we can calculate the number of moles that represents 25.7g of the same compound:

$N=\frac{mass(g)}{molarmass(\frac{g}{mol}} \\\\N=\frac{25.7g}{32.042\frac{g}{mol}}=0.8mol(methanol)$

Also, the molar heat of fusion of methanol is:

$u_{methanol}=3200\frac{J}{mol}=3.2\frac{kJ}{mol}$

Now, substituting into the first equation and calculating, we have:

$Q=N*u$

$Q=0.8mol*3.2\frac{kJ}{mol}=2.56kJ$

Hence, we have that the heat required to melt the compound is 2.56kJ.

Have a nice day!