Chemistry Notes: Metals: • A metal consists of a lattice of positive ions surrounded by a ‘sea’ of mobile delocalised valence electrons. • Metallic bonding is the electrostatic attraction between the delocalised electrons and the positive ions in the metallic lattice. Properties of metals: Property Explanation Relatively high density The particles are very close together. This is because of high electrostatic forces between the sea of valence electrons and the positively charged nucleus.
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IGCSE Chemistry 2012 exam revision notes by Samuel Lees Contents: 1. The particulate nature of matter 2. Experimental techniques 2.1 Measurement 2.2 (a) Criteria of purity 2.2 (b) Methods of purification 3. Atoms‚ elements and compounds 4.1 Atomic structure and the Periodic Table 4.2 Bonding the structure of matter 3.2 (a) Ions and ionic bonds 3.2 (b) Molecules and covalent bonds 3.2 (c) Macromolecules 3.2 (d) Metallic bonding 3 Stoichiometry 4
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multiple ions (i.e. Fe2+‚ Fe3+) due to proximity of 4s and 3d shells. 4.1.5 The ionic or covalent nature of the bonding in a binary compound is a result in the difference between their electronegativity. NaCl(s) is ionic‚ HCl(g) is (polar) covalent (note: covalent molecules tend to be gases/liquids‚ ionic tends to be solid‚ although network covalent would be solid). In general‚ if the difference between electronegativities is greater than 1.7‚ the bond will be more than 50% ionic. 4.1.6 Take
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UNIVERSITY FACULTY OF SCIENCE DEPARTMENT OF CHEMISTRY GUIDELINES FOR ORGANIC CHEMISTRY NON-MAJORS CHEM 181 By Dr. Haythem Ali Saadeh Fall‚ 2012 Course Title: ORGANIC CHEMISTRY for Non-Majors Course Number: CHEM 181 Prerequisite: General Chemistry Credit Hours: 2 Cr. Hrs. (comprises of 2 hrs. lecture per week) Course Instructor: Dr. Haythem Ali Saadeh h.saadeh@uaeu.ac.ae Textbook: “Organic Chemistry: A Short Course” By Harold Hart‚ Leslie E. Craine
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the admissibility of evidence into court( brought in peer review‚ same results and procedure) VII. Arriving at the Scene 1) Secure and Isolate 2) Record 3) Search 4) Collect 5) Chain of Custody 6) Standards 2) Record: Photography Video Sketches Notes 3) Search: spiral strip or line grid quadrant or zone 4) Collection: all pieces of evidence should be collected and packaged separately; wet or bodily floods go in
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Chemistry Lab Report (Design) Factors affecting Rates of a Reaction (Kinetics) KINETICS DESIGN LAB Research Question: Does the concentration of Potassium Iodide (KI) affect the rate of its reaction with hydrogen peroxide (H2O2) (of a fixed concentration)? Introduction: There are several factors that affect the rate of a reaction. Some of them being Pressure (if the reactants are Gases)‚ Temperature‚ Presence of a Catalyst‚ Surface Area of the reactant‚ and Concentration. According to
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Chemistry has sufficiently grown over time since it was first conducted by alchemists in the 17th century. It broke its mystical ties with alchemy‚ and took a turn to scientific investigation when a book called The Sceptical Chymist was written. Hundreds of scientists like Robert Boyle‚ Marie Curie‚ Joseph Achille Le Bel‚ and many others made important discoveries that contributed to chemistry. Joseph Achille Le Bel was a french chemist born on January 21‚ 1847 and grew up in Pechelbronn‚ France
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Extended Experimental Investigation Cold Pack Year 12 Chemistry Abstract: Cold packs are based on the principle of endothermic reactions‚ which means a reaction that absorbs heat from the surrounding resulting in a temperature drop. Due to this temperature drop‚ cold packs have many benefits when it comes to injuries such as sprains and strains. It cools the local tissue and reduces bleeding‚ swelling and pain. It also aids in a speedy recovery. The most commonly used
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ONE-SCHOOL.NET Short Notes: Form 5 Chemistry Rate or Reaction Calculation Rate of Reaction (Average Rate) Rates of reaction = Quantity change of reactants/products Total time for the reaction If the quantity change is immeasurable Rates of reaction = 1 Total time for the reaction Find the Rate From a Graph Average Rate Rates At an Instant The rate of reaction is equal to the slope of the graph The rate of reaction at an instant‚ t‚ is equal to the of quantity against
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References: Hebden Chemistry 12: Workbook for Students‚ Unit 1: Reaction Kinetics‚ pg. 1-36 Heath Chemistry Laboratory Experiments‚ Experiment 18 A: Factors Affecting Reaction Rate‚ pages. 192-196 Factors Affecting Reaction Rates http://chemwiki.ucdavis.edu/Physical_Chemistry/Kinetics/Factors_That_Affect_Reaction_Rates
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