Question

question 42
quarter 1 interim assessment
the analytical chemist receives a different mixture, which in this case is homogeneous and does not
form three distinct layers. the mixture is made of the compounds below.

1. (3 points) use the data above to describe the experimental process that the analytical

chemist should use to separate the mixture if she is tasked with keeping only the ethanol
and the sugar. be sure to explain, in words, what is separated in each step of the process,
and at what temperature this happens.

Explanation:

Step1: Heating the mixture

First, heat the homogeneous mixture. Ethanol has a lower boiling point (\(78^{\circ}C\)) than water (\(100^{\circ}C\)). So, when the temperature reaches \(78^{\circ}C\), ethanol will vaporize.

Step2: Condensing ethanol

The ethanol vapor is then condensed (using a condenser) to collect liquid ethanol.

Step3: Evaporating water

After ethanol is removed, continue heating. When the temperature reaches \(100^{\circ}C\), water will vaporize and escape (leaving sugar behind as sugar does not boil but decomposes above \(186^{\circ}C\) and we are not heating to that high a temperature when we just want to separate water from sugar in this context of keeping sugar).

Answer:

The chemist should use distillation. First, heat the mixture. At \(78^{\circ}C\), ethanol vaporizes. It is then condensed to collect liquid ethanol. Then, continue heating. At \(100^{\circ}C\), water vaporizes (escapes), leaving sugar behind.