Experimental Procedure

Pre$-$lab Preparation

For general information on how to prepare and maintain your lab notebook please refer to the chemistry lab book guidelines found in the Introduction to the lab manual.

Specifically for this lab, answer the following questions in your lab notebook as part of your prelab preparation.

In the reagent table draw out the Lewis Diagrams of malonic acid, biphenyl, water, ethanol, and diethyl ether.

Define $3$ of the following terms:

a$.$ Miscible

b$.$ Immiscible

c$.$ Boiling Point

d$.$ Melting Point

e$.$ Entropy

f$.$ Hydrophilic

g$.$ Hydrophobic

Give $2$ examples of a chemical property and $2$ examples of a physical property

How do you find a melting point range?

What is the formula for boiling point correction?

What is the corrected boiling point if your measured boiling point is $369C$ in a room where the atmospheric pressure is $669\mathrm{.}8mmHg?$

Suggested Readings From the Organic Chemistry Techniques review

Boiling point

Melting point

Refractometer

Solubility of Solid and Liquid Compounds

Place a small amount of malonic acid $($just dip the tip of the spatula into the bottle$)$ into each of four small dry test tubes. Label the test tubes and then add $1mL$ of water to the first tube, $1mL$ of methyl alcohol to the second tube, and $1mL$ of hexane to the third tube. The fourth tube will serve as a control. Determine the solubility of each sample in the following way: Using the small

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end of a spatula $($or the rounded end of a micro$-$spatula if available$),$ stir each sample continuously for $60$ seconds. If the solid dissolves completely, note how long it takes for the solid to dissolve. After $60$ seconds, note whether the compound is soluble, insolute or partially soluble.

Note! The volume of the solvent is approximate, you do not need to measure it with a graduated cylinder, you simply can assume that $1ml$ in a small test tube is about $1cm$ by its height, or the height is about the width of your index finger.

Repeat the directions above using biphenyl.

For each of the following pairs of liquid compounds, add $1mL$ of each liquid to the same test tube. Use a different test tube for each pair. Shake the test tubes for $10-20$ seconds to determine whether the two liquids are miscible or immiscible.

Note! The volume of the solvent is approximate, you do not need to measure it with a graduated cylinder, you simply can assume that $1ml$ in a small test tube is about $1cm$ by its height, or the height is about the width of your index finger.

Repeat the directions above using biphenyl.

For each of the following pairs of liquid compounds, add $1mL$ of each liquid to the same test tube. Use a different test tube for each pair. Shake the test tubes for $10-20$ seconds to determine whether the two liquids are miscible or immiscible.

Water and ethyl alcohol

Water and diethyl ether

Boiling Point Determination

You will determine the boiling point of an unknown sample using the micro$-$boiling point method as described in$.$ Read the instructions carefully. They are not repeated here. Your instructor will explain about the bubbles so listen carefully. $($In addition, the setup will be demonstrated by your instructor.$)$ Your lab instructor will also demonstrate how to obtain the pressure reading from the barometer in the classroom.

Record the barometric pressure value. You will need to use it when doing the calculation for the correction to the boiling point.

Choose a liquid unknown sample which can be any chemical from the list below. After determining the boiling point you will be able to identify your unknown based on its boiling point.

Take one of the boiling point unknowns, and record the unknown number, the state, and the color. Measure the boiling point, if you have time, repeat the experiment to check your accuracy.

Safety note! If the oil in the Thiele tube is cloudy or brown in colour let your lab instructor know, because it might need to be replaced with new oil.

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Safety note! If the oil in the Thiele tube is cloudy or brown in colour let your lab instructor know, because it might need to be replaced with new oil.

$\backslash$table$[[$Name$,$Boiling Point,Name,Boiling Point$],[$p$-$xylene,$138C,2-$butanol,$97C$