The molar heat of vaporization of ethanol is 43.5 kJ/mo. Calculate the heat required to vaporize 25.0 g of ethanol at its boiling point.
Ethanol is (2C 5H OH)
Could someone please write the equation? (is the equation q=CmT)
I wonder if that is kJ/month or kJ/mol. I assume kJ/mol. No, the equation isn't q = CmT. It's mass x delta Hvap.
Yes, the equation you mentioned, q = CmΔT, can be used to calculate the heat required to vaporize a substance. However, this equation needs some modification to account for the phase change. The correct equation for calculating the heat required for vaporization is q = nΔHvap, where q is the heat, n is the number of moles of the substance, and ΔHvap is the molar heat of vaporization.
To find the value of n, we need to convert the given mass to moles. The molar mass of ethanol (C2H5OH) is calculated as follows:
(2 × atomic mass of C) + (5 × atomic mass of H) + (1 × atomic mass of O) = (2 × 12.01 g/mol) + (5 × 1.01 g/mol) + (1 × 16.00 g/mol) = 46.08 g/mol
Now, we can convert the given mass of 25.0 g to moles:
moles = mass / molar mass = 25.0 g / 46.08 g/mol ≈ 0.5413 mol
Finally, we can use the equation q = nΔHvap to calculate the heat required to vaporize the given amount of ethanol:
q = 0.5413 mol × 43.5 kJ/mol
q ≈ 23.6 kJ
Therefore, the heat required to vaporize 25.0 g of ethanol at its boiling point is approximately 23.6 kJ.
To calculate the heat required to vaporize a substance, you can use the equation q = m × ΔHvap, where q represents the heat, m is the mass of the substance, and ΔHvap is the molar heat of vaporization.
In this case, you are given the molar heat of vaporization of ethanol as 43.5 kJ/mol. However, you need to calculate the heat required to vaporize 25.0 g of ethanol at its boiling point. To do this, you'll need to convert the mass into moles.
To calculate the number of moles, you need to know the molar mass of ethanol. The molecular formula of ethanol (C2H5OH) indicates that it contains 2 carbon atoms (C), 6 hydrogen atoms (H), and one oxygen atom (O).
To determine the molar mass, you can use the atomic masses from the periodic table:
- Carbon (C): 12.01 g/mol
- Hydrogen (H): 1.008 g/mol
- Oxygen (O): 16.00 g/mol
Now, you can calculate the molar mass of ethanol using the formula:
Molar mass of ethanol = (2 × Molar mass of carbon) + (6 × Molar mass of hydrogen) + Molar mass of oxygen
= (2 × 12.01 g/mol) + (6 × 1.008 g/mol) + 16.00 g/mol
= 46.07 g/mol
So, the molar mass of ethanol is 46.07 g/mol.
To convert the given mass of 25.0 g into moles, divide the mass by the molar mass:
Number of moles = Mass / Molar mass
= 25.0 g / 46.07 g/mol
Now you have the number of moles of ethanol. Finally, you can calculate the heat required to vaporize by multiplying the number of moles by the molar heat of vaporization:
q = (Number of moles) × ΔHvap
Substituting the values:
q = (25.0 g / 46.07 g/mol) × 43.5 kJ/mol
Simplify and calculate to get the final answer.