Calculate the heat required to melt 25.7 g of solid methanol at its melting point.t. Refer to Table 15.4.

Answer 1

In Table 15.4, the heat of fusion for methanol is listed as 3.97 kJ/mol. To calculate the heat required to melt 25.7 g of solid methanol, we need to convert mass to moles first.

The molar mass of methanol (CH3OH) is:
1 carbon (C) = 12.01 g/mol
4 hydrogen (H) = 4.03 g/mol
1 oxygen (O) = 16.00 g/mol
1 hydrogen (H, in the hydroxyl group) = 1.01 g/mol

So, the molar mass of methanol (CH3OH) = (12.01 x 1) + (1.01 x 4) + 16.00
= 32.04 g/mol

Now, we can calculate the number of moles of methanol by dividing the given mass by the molar mass:
n = m/M
n = 25.7 g / 32.04 g/mol
n ≈ 0.802 mol

Finally, we can calculate the heat required to melt methanol using the heat of fusion:

Heat required = n x heat of fusion
Heat required = 0.802 mol x 3.97 kJ/mol
Heat required ≈ 3.18 kJ

Therefore, the heat required to melt 25.7 g of solid methanol at its melting point is approximately 3.18 kJ.