The enthalpy of fusion of methanol (CH3OH) is 3.16 KJ/mol. How much heat would be absorbed or released upon freezing 25.6 grams of methanol?
2.52 kj released
q = mass x heat fusion.
q = 25.6g x (1 mol/molar mass CH3OH) x 3160 J = ? J and you know that freezing is an exothermic reaction; therefore, the ?J will be released.
thank you, i see where i messed up now
2.52 KJ Released #trustme
wsp
Well, methanol must have really strong dramatic skills if it can freeze and release heat at the same time! But, let's put the jokes aside for a moment and do some math.
First, we need to convert the mass of methanol from grams to moles. The molar mass of methanol (CH3OH) is approximately 32 grams per mole. So, 25.6 grams of methanol is equal to 25.6/32 = 0.8 moles.
Now, we can calculate the amount of heat absorbed or released using the enthalpy of fusion. The enthalpy of fusion is given as 3.16 kJ/mol.
Heat absorbed or released = enthalpy of fusion × number of moles
Heat absorbed or released = 3.16 kJ/mol × 0.8 moles
Heat absorbed or released = 2.528 kJ
So, approximately 2.528 kJ of heat would be absorbed or released upon freezing 25.6 grams of methanol.
To calculate the heat absorbed or released upon freezing a specific amount of a substance, we need to use the equation:
q = m * ΔHf
Where:
q is the heat absorbed or released (in joules),
m is the mass of the substance (in grams),
ΔHf is the enthalpy of fusion (in joules per mole).
However, note that the given enthalpy of fusion is in kilojoules per mole, so it needs to be converted to joules per mole before using it in the equation.
To convert the enthalpy of fusion from kilojoules per mole to joules per mole, we can use the conversion factor:
1 kilojoule = 1000 joules
So, the enthalpy of fusion of methanol in joules per mole would be:
ΔHf = 3.16 KJ/mol * 1000 J/KJ = 3160 J/mol
Now, we can proceed with the calculation:
First, convert the mass of methanol from grams to moles. To do this, we need to know the molar mass of methanol (CH3OH).
The atomic masses of carbon (C), hydrogen (H), oxygen (O), and the molar mass of methanol (CH3OH) are approximately:
C: 12.01 g/mol
H: 1.01 g/mol
O: 16.00 g/mol
Molar mass of CH3OH = (12.01 g/mol * 1) + (1.01 g/mol * 4) + (16.00 g/mol * 1) = 32.04 g/mol
Next, we can calculate the number of moles (n) of methanol using the given mass (m) and molar mass (M):
n = m / M
n = 25.6 g / 32.04 g/mol
Now, we can substitute the values into the heat equation:
q = m * ΔHf
q = (25.6 g / 32.04 g/mol) * 3160 J/mol
Calculating the above expression will give you the amount of heat (q) absorbed or released upon freezing 25.6 grams of methanol.