Part A: Property change upon mixing
Refer to WHO recommendation of making hand santizer.
https://www.ncbi.nlm.nih.gov/books/NBK144054/
The suggested composition of ethanol-based handrub forumulation for microbicidal activity is
ethanol 80% v/v, glycerol 1.45% v/v, hydrogen peroxide (H2O2) 0.125% v/v with the balance
being water. It is suggested to mix 96% v/v of ethanol with other components to achieve a final
composition of 80%v/v ethanol. In molar terms, this corresponds to 67 mol% ethanol.
We will ignore the other components (glycerol and hydrogen peroxide) for simplicity of
calculations and consider only a binary mixture of ethanol and water. We will consider that we
have access to two ingredients: (i) 96% v/v of ethanol in water and (ii) water
i. Recognizing that there is a volume change upon mixing of ethanol and water, you are asked
to determine the respective volumes of water and 96% v/v ethanol needed to create a final
volume of 50L at 298K of hand sanitizer containing 67 mol% ethanol.
The density of pure water, pure ethanol and ethanol-water mixtures has been reported by
Grolier, Fluid Phase Equilibria, 6 (1981) 283-287. Excess volume relationship has also been
reported in the paper
ii. Refer to part (i). If the mixing process was to be carried out isothermally, determine the total
heat need to be removed or added. Clearly state whether heat is needed to be added or to be
removed.
The enthalpy of mixing of water and ethanol has been reported by Boyne and Williamson J.
Chem. Eng. Data 1967, 12, 3, 318
Detailed calculations are expected for each part.