[Pharmaceutical Chemistry] Melting Point and Boiling Point Determination

2. a) Liquid nitrogen boiling at -196°C is a physical property because it describes the boiling point of a substance, which is also when it changes state. A change of state, from a liquid to a gas, is a physical property because there is no new substance being created.

I. LIQUID - Identification of an Unknown Liquid: Using the physical properties of Solubility, Density, and Boiling Point.

After each of the solids were completely dry, each was placed into a MelTemp device. The temperature at which each solid began to melt and completed melting was recorded.

3% hydrogen peroxide, a household blender, potatoes (3 medium size potatoes, that are peeled and quartered), tap water, 8 test tubes, 8 transfer pipets, sugar packets, salt, a small saucepan, a refrigerator with a freezer, stove, 4 clear plastic cups, tongs (to remove test tubes from boiling water), 4 coffee cups, cheesecloth to filter the potato extract, a wax pencil or Sharpie marker, a ruler, scale or balance, 250 ml graduated cylinder, and oven mitt or tongs.

In determining the melting point range of the aspirin, a capillary tube (sealed at one end) was one-third-filled with the dried aspirin. The capillary tube and a thermometer were immersed in an oil bath. The temperature at which the solid started to melt and the temperature when the entire sample was completely liquefied were recorded as the melting point temperature range.

Temperature: Measure of the average speed of molecules rather than the total amount of heat energy in matter.

What is its melting point? 1,405 K: 1,132 C: 2,070 F. boiling point? 4,404 K: 4,131 C: 7,468 F

Evaporation- when water evaporates in the form of water vapor by the heat of the

Discussion: As seen in the melting point determination, the average melting point range of the product was 172.2-185.3ºC. The melting points of the possible products are listed as 101ºC for o-methoxybenzoic acid, 110ºC for m- methoxybenzoic acid, and 185ºC for p- methoxybenzoic acid. As the melting point of the sample

The objective of this lab is to synthesize acetaminophen from p-aminophenol. The techniques used to do so, consist of: reflux with heat to allow reaction to occur at a reasonable time period, extraction and filtration to isolate the desired product, and characterization of the product by analyzing IR spectras and melting points. Acetaminophen considered synthesized, primarily due to the IR spectrum exhibiting all the bond vibrations is the amide group. The percent yield of 124.6% imply that there was a mechanical error that occurred, thus, also tampering with the progression of the chemical reaction. The wide melting point range of 165 C-169 C denote the impurity of the acetaminophen product.

The lab used methods of calorimetry in order to measure the temperature change of reactions and calculate the changes in

Solubility – Very soluble (water), Freely soluble (methylene chloride, chloroform, alcohol), Slightly soluble (acetone) and Insoluble (ether).6 Melting point - 120°C or 248°F.5

The purpose of this experiment is to identify an unknown substance by measuring the density and boiling point. I will be able to conclude which substance is my own from a list of known options stating what its real boiling point and density is.

The volume is definite if the temperature and pressure are constant. When a solid is heated above its melting point, it becomes liquid, given that the pressure is higher than the triple point of the substance. Intermolecular (or interatomic or interionic) forces are still important, but the molecules have enough energy to move relative to each other and the structure is mobile. This means that the shape of a liquid is not definite but is determined by its container. The volume is usually greater than that of the corresponding solid, the most well known exception being water, H2O. The highest temperature at which a given liquid can exist is its critical temperature.[5]

An alcohol bath was prepared with an ethanol solution and dry ice, the solution was measured using a thermometer, at approximately -15˚ the bath was placed under a Polaroid filter and above a stable jar upon a white piece of paper. The capillary level holder with the frozen capillary tubes was placed carefully into the bath (at an angle to reduce effervescence). A lamp was placed 20 cm away from the setup and shone on the Polaroid filter. This setup ensured the ethanol solution didn’t heat up too rapidly.