How much heat is evolved when 25.5 g of benzene freezes at 5.5 Celcius (molar heat of fusion is 9.94 kJ/mol and molar mass of benzene= 78.0 g/mol)
q = mass x delta Hfusion.
Change 25.5 g to moles. moles = grams/molar mass.
Note the correct spelling of celsius.
To find the heat evolved when benzene freezes, we need to use the formula q = m * ΔHf, where q is the heat evolved, m is the mass of the substance, and ΔHf is the molar heat of fusion.
First, we need to convert the given mass of benzene into moles. We can do this by dividing the mass by the molar mass of benzene:
Number of moles of benzene = Mass of benzene / Molar mass of benzene
= 25.5 g / 78.0 g/mol
Next, we need to calculate the heat evolved. We can use the equation:
q = m * ΔHf
where m is the number of moles of benzene.
Substituting the values we have:
q = (25.5 g / 78.0 g/mol) * (9.94 kJ/mol)
Calculating this equation will give us the amount of heat evolved (q) when 25.5 g of benzene freezes at 5.5 degrees Celsius.