The Melting Point And Boiling Point Of Halogenoalkanes

The melting point of benzoic acid is 122.35 °C [5]. The melting point determined from the experiment is a range from 118°C - 120°C. The reason for the experiment producing a melting range compared to a melting point is due to impurities as well for the reason of a lower melting point [1]. Impurities within the product lowers the melting point due to intermolecular forces, this causes benzoic acid to not have as strong of a bond together in its crystal structure as there are impurities in the way. This allows a lower level of heat to melt the benzoic

While the other two compounds melted within a couple of seconds. Vapor might have formed on the sides of the test tube for unknown 1 because of the reason that the distilled water within the compound began to evaporate. If the distance between the flame and the test tube differed, the test might have gone wrong, yielding in incorrect results. Because of the strength of ionic compounds, it takes more energy to break their bonds. With the rise of heat, comes the rise of energy, which is the reason why ionic compounds have high melting points as well as high boiling points. The melting point of sodium chloride is 801°C and copper chloride is 498°C. The melting point of citric acid is 153°C and sucrose is

to portray its pressure/volume/temperature behaviours. We will use the temperature of the boiling water (T), ambient pressure (P), volume (V) and the ideal gas constant (R = 8.31451 J/mol K) to calculate the number of moles (n) of the compound and then, furthermore, the molar mass of the substance.1

In order to discover the melting point range of Unknown 33A, a Digimelt was utilized. Melting point is the temperature at which a crystalline structure changes from solid to liquid. By adding thermal energy, the structure changed from solid to liquid. The thermal energy increased the kinetic energy, which then overcame the intermolecular attractive forces between the molecules. This increase in speed allowed the molecules to move more freely. By identifying the melting point range of Unknown 33A, it narrowed the possibilities of the unknown by ruling out the compounds with melting points greater than ± 20°C from Unknown 33A’s melting point range.

Ionic boding is when an atom gives another electron to another to form an ionic bond. One atom will donate an electron to another to fill its outer shell, that is held together by Electrostatic attraction. These bonds involve Cations, which are positive Ions that are mostly metals and Anions which are negative Ions that are mostly non-metals. An example of this would-be Sodium and Chlorine. Sodium has one electron on its outer shell, Chlorine has seven electrons on its outer shell. Chlorine needs eight electrons on its outer shell to make it stable. Sodium has a spare electron, so will donate it to Chlorine. Na + Cl = NaCl

The melting point of a chemical is a physical property inherent to that substance. The chemical changes from a solid to a liquid state, but the composition remains the same. It can be used to determine the identity of an unknown substance. The purpose of this experiment was to discover the identity of an unknown chemical by determining its melting point.

Organic chemists use melting points to identify compounds and determine its purity. Two temperatures that need to be noted are the point at which the first drop of liquid appears from the substance and the point at which the entire mass of the solid substance turns to liquid. The range between these two points is the melting point. The melting point is used to determine the purity of a substance because if the substance is pure then its melting point will be higher. Also, if the substance is pure then its melting point will be narrower. The melting point will be lower if the substance is impure. Melting point can be used to identify an unknown compound by mixing it with a known substance with a known melting point. If it is the correct material

Molecules that are covalently bonded have low melting points because the electrons are being shared. Plus, they are terrible conductors of electricity, because the molecule is made up of nonmetals.

The objective of this experiment was to investigate the relationship of dispersion forces and hydrogen bonding forces in intermolecular attractions through the evaporation of different substances. Using temperature probes, the endothermic process of evaporation is measured by inserting the probes into the substance and then taking them out to allow the substance to evaporate, the change in temperature of the substances showed if a lot or not a lot of evaporation occurred and over how long the evaporation took place depending on if the change in temperature was high or low.

Improvements to the Ideal Gas law for substances at high temperature and pressure is accomplished via van der Waals model; which tweaks the ideal gas law formula by accounting for the volume the substances molecules and the intermolecular forces between molecules. These small changes greatly improve predicting the properties of pure substances, such as the solid/liquid/gas phase boundary for pure substances I was initially unclear as to the texts description explaining liquid-gas interaction, ... eventually a point is reached where there is no longer any discontinuous change from liquid to gas. This point is called the critical point, but upon further reflection its clear that above the critical point, temperature is not constant during

1. What two effects do impurities have on the melting point of an organic compound?

The melting point usually increases when you go from the element sodium to silicon however then starts to decrease when it gets to argon. The boiling point will usually increase when going from sodium to aluminium but will then decrease to argon.

When the particles have reached a certain point the kinetic energy is stronger than the attraction between the atoms and the particles have no limitations on their movement, they have reached their boiling point and have become a gas.

By sharing electrons, atoms within a molecule that are attracted to one another is called an intramolecular force. Between the molecules intermolecular force, the physical properties for example the melting points and boiling points, relate to the solubility and the strength of these force.

Melting points were determined on a Perfit melting apparatus (Ambala, Haryana, India) and are uncurrected. UV spectra were measured with a Lambda Bio 20 spectrophotometer (Perkin-Elmer-Rotkreuz, Switzerland) in methanol. Infra red spectra were recorded on Shimadzu FTIR 5000 (FTS 135, Japan) spectrophotometer using KBr pellets; γmax values are given in cm-1. 1H and 13C NMR spectra were screened on advance DRX 400, Bruker spectrospin 400 and 100 MHz instrument in 5 mm spinning tubes at 27 ºC, respectively (Karlesruthe, Germany) using TMS as an internal standard. Mass spectra were scanned by effecting FAB ionization at 70 eV on a JEOL-JMS-DX 303 spectrometer (Japan) equipped with direct inlet probe system. Column chromatography was performed on silica gel (60-120 mesh; Qualigen, Mumbai, India). TLC was run on silica gel G (Qualigen). Spots were visualised by exposing to iodine vapours, UV radiation, and spraying with ceric sulphate solution.