design a procedue to separate a mixture that contains menthol,ethanol and 1 pentanol. explain with references to intermolecular forces why your procedure is effective for seperation this mixture
Look up the boiling points for methanol, ethanol, and 1-pentanol and see if they are candidates to be seaprated by fractional distillation.
The question asks about separating menthol (not methanol), ethanol and 1 pentanol.
These can be separated by fractional distillation as the boiling points are widely spaced.
menthol 216C
ethanol 78C
1-pentanol 137C
To separate a mixture containing menthol, ethanol, and 1-pentanol, we can employ a procedure called fractional distillation. This method takes advantage of the differences in boiling points of the components, which are influenced by the intermolecular forces present in each compound.
Here is a step-by-step procedure for the separation:
1. Set up a fractional distillation apparatus, including a distillation flask, a fractionating column, a condenser, and a collection flask.
2. Add the mixture of menthol, ethanol, and 1-pentanol to the distillation flask.
3. Apply heat to the distillation flask, gradually increasing the temperature. As the heat increases, the components of the mixture will start vaporizing.
4. The vaporized compounds will rise through the fractionating column. The column contains several glass beads or plates, which provide a large surface area for the vapor to condense and revaporize.
5. Each compound in the mixture will have different boiling points due to variations in their intermolecular forces. Menthol, being a solid, will sublime directly from a solid to a gas (sublimation) and collects separately from the liquid distillates. Ethanol, with hydrogen bonding as its primary intermolecular force, will have the lowest boiling point among the three. 1-pentanol, also with hydrogen bonding but having a longer carbon chain, will have a higher boiling point.
6. As the temperature increases further, the ethanol vapor will rise to the top of the fractionating column and condense on the cool glass beads/plates. The condensed liquid will then flow back down into the distillation flask.
7. The condensed ethanol, now separated from the mixture, will be collected in a separate flask.
8. As the temperature continues to rise, 1-pentanol vaporizes and follows a similar process as ethanol, rising up and condensing. 1-pentanol is collected separately in another flask.
By utilizing fractional distillation, we can separate the mixture based on the differences in boiling points, which are related to intermolecular forces. This method takes advantage of the weaker London dispersion forces present in menthol, the stronger hydrogen bonding in ethanol, and the stronger hydrogen bonding and longer carbon chain in 1-pentanol.
References:
- AkrosChemicals. (2021). Fractional distillation setup [Image]. Wikimedia Commons. Retrieved from https://commons.wikimedia.org/wiki/File:Fractional_distillation_setup.png
- Chang, R. (2010). Physical Chemistry for the Biosciences. University Science Books.