Bromination of Arenes This lab demonstrated the application of adding bromine to various arenes, hydrocarbons with alternating single bonds. This process, bromination, is a mechanism which treats hydrogen as a functional group. This being the case, the rate of reaction of certain arenes can be measured and compared to that of other arenes upon the addition of the bromine. The reaction occurs when the bromine radical generates from the halide diatomic molecule, using light energy. The fact that the energy needed to break the necessary bonds falls within the visible light spectrum is the basis on which the experiment is based.
As Model Science (2011) explains, the experiment will show that as the salt with the metal is “burned, the electrons will be excited (i.e., move to another energy level) and as these electrons fall back from one energy level to another, they will emit photons of light. These photons will have different colors depending on the element and its discrete energy levels”. In other words, “different wavelengths of light (colors) will be emitted when the electrons of different elements go down the step(s) between their energy level(s). In addition, each element will have its own set of energy levels and therefore each will have its own color or set of colors (Model Science, 2011)”. As an example, Model Science (2011) provided “sodium burns orange, potassium -purple/blue, barium - green, and lithium – red”.
The arrangement of particles in an atom Protons and neutrons make up the main, dense, central nucleus in the centre of the atom. This is surrounded by electrons “orbiting” the main nucleus. The electron are in shells depending on their energy levels, as the most energetic are on the outer shells, because they need more energy to travel around a bigger “orbit” of the nucleus. These shells are full when a certain amount of atoms are in the shell; 2 in the first shell, 8 in the next shell, 8 in the third shell and so on. When the shells are full, the atom is unreactive.
An ionic bond is the transfer of valence electrons between atoms. It is a type of chemical bond that creates two oppositely charged ions. In ionic bonds, the metal loses electrons to become a positively charged cation, the non-metal accepts those electrons to become a negatively charged anion. Ionic bonds require an electron donor, metal, and an electron acceptor, nonmetal. By losing those electrons, these metals can achieve noble-gas configuration and satisfy the octet rule.
Nitration of Methylbenzoate Aim: The aim of the experiment is to successfully perform the nitration of Methylbenzoate by the recrystalisation method and in doing so obtaining a melting point and the infra-red spectra graph of the product. Introduction: Methylbenzoate is an aromatic compound and it is structurally related to Benzene. It has an electron rich aromatic ring which makes it vulnerable to electrophiles this in turn making them react. A common electrophile is used in this reaction, which is the NO2+ nitronium ion. It is produced by reacting nitric acid and sulphuric acid simultaneously.
Simple and Fractional Distillation of Cyclohexane and Toluene Purpose: The purpose of this experiment was to become familiar with the processes of simple and fractional distillation. In this experiment a mixture of two volatile compounds, cyclohexane and toluene, were separated with the process of distillation. Distillation relies on each compound having distinct and separate boiling points. The pure products were analyzed with gas chromatography to determine the success of the distillation. Introduction: Distillation is the process of heating a liquid until it boils, then condensing and collecting the resulting hot vapors.
Then weigh the crucible without the hydrate after heating. Record both masses. Next, add CoCl2 ∙6H2O and weigh the crucible. Now place the hydrate and crucible on the hot plate. Observe the color change while it is being heated.
A wet swab was used to collect a small sample of the compound. The swab was placed over a Bunsen burner and the flame’s color was recorded. The flame test color of the unknown cation was then compared with the known cations, listed
Nuclear fussion: Nuclear fusion is the process in which two light nuclei combine to form a heavier nucleus. The total masses of the products are less than the combined mass of the two light nuclei. The energy equivalent of the loss of mass is released. The release of energy during nuclear fusion can also be calculated from the values of the
The nucleus is surrounded by circling electrons on the outer shell. In most cases, atoms are neutrally charged (there is the same number of electrons as protons). If an atom has more electrons than protons, it is negatively charged. If an atom has more protons than electrons, it is positively charged. Static electricity is produced from a process known as triboelectrification.