that "What Is" be viewed as a constant. Heraclitus’ focus was on elements transferring to and from opposites. Parmenides concentrated on a sense of "being." Heraclitus believed in a flux or "Yin and Yang" in the world that promoted harmony and stability‚ "What is opposed brings together‚ the finest harmony is composed of things at variance." (pg29‚ frg49) For Parmenides‚ "What Is" leads us to the truth about our universe‚ in that it is timeless‚ eternal‚ motionless‚ perfectly uniform‚ the same
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year in restoring rusted materials caused by corrosion. Corrosion can take place in many forms as a result of oxidation and rust. Almost any material that comes in contact with oxygen will become at risk of corrosion. Corrosion in metals Metal atoms give up electrons and became positively charged ions when exposed to an environment containing water (H2O or air (O2) molecules. Sea water for instance enhances growth of the fatigue crack. The corrosive process of the metal dissolving as ions generates
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Heterogeneous Catalysis Hydrogenation • On solids‚ the accepted mechanism today is called the Horiuti1. Binding of the unsaturated bond‚ and hydrogen dissociation into atomic hydrogen onto the catalyst 2. Addition of one atom of hydrogen; this step is reversible 3. Addition of the second atom; effectively irreversible under hydrogenating conditions. M SN 53 2 C ou rs e M at er ia Polanyi mechanism. ls Examples of Heterogeneous Catalysis
Free Catalysis
Chemistry Reference Tables Name Avogadro’s number Value 6.022 × 1023 particles/mole 0.0821 L atm mole K L mmHg 62.4 mole K 8.314 L kPa mole K 1.00 atm = 101.3 kPa = 760. mmHg = 760. torr 0°C or 273K 22.4 L Symbol Value Gas constant (R) Standard pressure Standard temperature Volume of 1 mole of any gas at STP Thermodynamic Constants Heat of fusion of water Heat of vaporization of water H f (water) Hv (water) 334 J/g 2‚260 J/g J for ice‚ 2.02 J for steam‚ g°C g°C J for liquid 4.18
Free Hydrogen Oxygen Chlorine
Chlorobenzene is less reactive than chloromethane. Ans. In chlorobenzene‚ each carbon atom of benzenering is sp2 hyridised and is electron withdrawing. Chlorine atom donates a lone pair of electron and acquire positive charge. The negative charge is delocalised on ortho and para position by resonance. C-Cl bond acquires partial double bond character and is 169 pm as compared to 17.0 pm in chloromethane where C atom is sp3 hybridised. So larger amount of energy is required to break C-Cl bond in chlorobenzene
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Alkyl Halides Alkyl halides are a class of compounds where a halogen atom or atoms are bound to an sp3 orbital of an alkyl group. CHCl3 (Chloroform: organic solvent) CF2Cl2 (Freon-12: refrigerant CFC) CF3CHClBr (Halothane: anesthetic) Halogen atoms are more electronegative than carbon atoms‚ and so the C-Hal bond is polarized. H H μ C + C-l δ δ H The C-X bond is polarized in such a way that there is partial positive charge on the carbon and partial negative charge on the halogen. Dipole moment
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6.1 ABSTRACT The densities (ρ) and viscosity (η) were reported for binary mixtures of N-methylformamide with O-substituted aniline (2-chloroaniline‚ 2-methylaniline and 2-methoxyaniline) over the entire composition range from 303.15 K to 318.15 K and at atmospheric pressure 0.1 MPa. These experimental data have been used to calculate excess volume (VE)‚ deviation in viscosity (∆η) and excess Gibbs energy of activation of viscous flow (G*E). The variations in these properties with composition for
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secondary structure refers to segments of polypeptide chains which are folded or coiled‚ as a result of hydrogen bonding on the polypeptide backbones. (Reece‚ 2011). The electrognetaive oxygen and nitrogen atoms both have a partial negative charge and attach to the weakly positive hydrogen atom. (Reece‚ 2011). There are two secondary structures that can form: an ɑ helix‚ with hydrogen bonding every fourth amino acid‚ and a β pleated sheet when the polypeptided backbones bond to form parallel or anti-parallel
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CH3F + AgBr is known? (a) Grignard (b) Wurtz (c) Fitting (d) Swartz 9) What are nucleophilic reagents according to Lewis theory? (a) Acid (b) Base (c) Neutral molecules (d) Positive ions 10) On which of the following factors the stability of carboncation depends? (a) Resonance (b) Temperature (c) Transition state (d) Reaction rate 11) What is called an optically active substance? (a) which reflects polarized light (b) which rotates the plane of polarized light (c)
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table. Part B - Multiple Choice D A 1. A(n) __ is used to represent a compound. a) symbol b) equation c) subscript d) formula 2. ___ atoms or groups of atoms are called ions. a) charged b) diatomic c) neutral d) monatomic A 3. For the formula of a compound to be correct‚ the algebraic addition of the charges on the atoms or ions in the compound must add up to __. a) zero b) one c) two d) four D 4. Potassium bromide is an example of a(n) __ compound. a) molecular
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