BroIn this experiment of the relative rates of free-radical chain bromination‚ we were expected to be able to determine the relative reactivates of the many types of hydrogen atoms involved toward bromine atoms. Bromination is defined to be a regioselective reaction meaning bromine has preference of making or breaking a bond over all other directions that it may have had available. In this case‚ Markovnikov’s rule is revealed to be the case in this situation that states that adding a protic acid
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from collisions between the particle and air molecules. This experimental evidence for kinetic theory‚ pointed out by HYPERLINK http//en.wikipedia.org/wiki/Albert_EinsteinAlbert Einstein in 1905‚ is generally seen as having confirmed the existence of atoms and molecules. HYPERLINK http//en.wikipedia.org/wiki/Kinetic_theoryhttp//en.wikipedia.org/wiki/Kinetic_theory Postulates The theory for ideal gases makes the following assumptions The gas consists of very small particles‚ all with non-zero HYPERLINK
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hydrogen‚ oxygen‚ and carbon atoms form to form a sucrose molecule (C12H22O11). Ionic bonds form when oppositely Figure 1: The pile of white grains on the left are ordinary crystals of table salt and the grains on the right are charged atoms‚ referred to as ions‚ grains of white‚ refined sugar. Notice that the salt grains combine. Under the right conditions‚ are more cubic in shape. when individual sodium and chlorine atoms associate‚ an electron transfer will occur. The sodium atom contains a single electron
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respective periods. Down the group‚ the size of alkali metals increases whereas ionization enthalpy decreases. 4. Alkali metals have low densities and densities increases from Li to Cs. (Exception: K is lighter than Na‚ due to bigger size of potassium atom). 5. Alkali metals have low melting and boiling points due to their loosely packed metallic lattices. 6. Alkali metals‚ except lithium‚ show photoelectric effect. Due to small size and high ionization enthalpy‚ the electrons of lithium cannot
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Name: __________________________________ ( ) Class: 4Q HWA CHONG INSTITUTION PRELIMINARY EXAMINATION 2010 CHEMISTRY 5072 Paper 1 Time: 1 hour INSTRUCTIONS TO CANDIDATES Do not turn the pages over until you are told to do so. Write your name and index number on the answer sheet in the spaces provided. There are forty questions on this paper. Attempt all questions. For each question‚ there are four possible answers labelled A‚ B‚ C and D. Choose the one you consider correct and
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attack the rather acidic (pKa ~ 20) α-hydrogen of the ketone. This acidity is due to the stability of the resonance structures of the corresponding enolate ion that forms upon dissociation. When the hydroxide is able to subtract a hydrogen atom‚ a carbanion is formed. This carbanion is a very strong base and is able to attack the chlorine thus taking one of the chlorine atoms. The introduction of one chlorine atom catalyzes the attack of another hydroxide molecule on the remaining α-hydrogens of the
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“moves” from the cation to the anion‚ and an ionic compound “linking” the two ions is formed. • In a stable state (i.e.‚ a full outer shell or a full VALENCE OCTET of electrons) ‚ the energy state is at its lowest. This is preferred. This is stability. Elements seek to be at this low energy state. Breaking the ionization energy hold or
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NOT “rocket science” 1.2 1. COVALENT BONDING & SHAPES OF MOLECULES [text 1.1-1.7] ( © Chemistry Dept‚ University of Western Ontario‚ 2011) - largely a review of essential material from year-1 chem A. Electronic Structure of Atoms - The bonding behaviour of atoms depends entirely on electron configuration‚ as revealed by an atom’s position in the Periodic Table. - The "Organic Chemist’s" periodic table. Key to numbers: - upper left = atomic number = number of electrons - lower left = number
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terminology‚ the primary valency corresponds to the oxidation number of the metal ion‚ whereas the secondary valency refers to the coordination number of the metal ion. (ii) A metal ion has a definite number of secondary valencies around the central atom. Also‚ these valencies project in a specific direction in the space assigned to the definite geometry of the coordination compound. (iii) Primary valencies are usually ionizable‚ while secondary valencies are non-ionizable. Question 9.2: FeSO4 solution
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Chemical Bonds Chemical Bond: is the force that holds atoms together in a compound. They form because they lower the potential energy of the charged particles that compose atoms. Chemical bonds can be broadly classified into two types: Ionic and Covalent. Ionic: metal & nonmetal Metals have a tendency to lose electrons and nonmetals have a tendency to gain them. The metal atom becomes a cation and a nonmetal becomes an anion. The oppositely charged ions attract one another and form an ionic
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