Given: hexane-
-density at 25 degrees Celsius (.660g/ml)
-Vapor pressure of pure substance at 25 degrees Celsius (150 torr)
-heat if vaporization (21.0 kj/mol)
-55 mL
What mass of hexane vaporizes at 25 degrees Celsius?
All of it if you give it enough time.
To find the mass of hexane that vaporizes at 25 degrees Celsius, we need to use the given information about density, volume, and heat of vaporization. Here is how you can find the answer:
1. Convert the given volume of hexane (55 mL) to grams:
Since the density of hexane is given as 0.660 g/mL, we can multiply the volume (55 mL) by the density to get the mass in grams.
Mass = Volume × Density
Mass = 55 mL × 0.660 g/mL
Mass = 36.3 grams
2. Convert the mass of hexane to moles:
To convert grams to moles, we need to know the molar mass of hexane. The molar mass of hexane is the sum of the atomic masses of the atoms in its chemical formula (C6H14).
Molar mass of hexane = (6 × atomic mass of carbon) + (14 × atomic mass of hydrogen)
Molar mass of hexane ≈ (6 × 12.01 g/mol) + (14 × 1.01 g/mol)
Molar mass of hexane ≈ 86.18 g/mol
Now we can convert the mass of hexane from grams to moles:
Moles = Mass / Molar mass
Moles = 36.3 g / 86.18 g/mol
Moles ≈ 0.4212 moles
3. Calculate the heat energy required to vaporize the given amount of hexane:
The heat of vaporization of hexane provided is 21.0 kJ/mol. So, to find the heat energy required to vaporize the moles of hexane, we can use the following formula:
Heat energy = Moles × Heat of vaporization
Heat energy = 0.4212 moles × 21.0 kJ/mol
Heat energy ≈ 8.85 kJ
Therefore, the mass of hexane that vaporizes at 25 degrees Celsius is approximately 36.3 grams, and it requires approximately 8.85 kJ of heat energy to vaporize it.