household detectors‚ known as smoke alarms‚ generally issue a local audible or visual alarm from the detector itself. Smoke detectors are typically housed in a disk-shaped plastic enclosure about 150 millimetres (6 in) in diameter and 25 millimetres (1 in) thick‚ but the shape can vary by manufacturer or product line. Most smoke detectors work either by optical detection (photoelectric) or by physical process (ionization)‚ while others use both detection methods to increase sensitivity to smoke. Sensitive
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Vibrating Bonds and the Greenhouse Effect • 4.3 Lewis Structures • 4.6 Resonance • 4.7 Formal Charge: Choosing among Lewis Structures • 4.8 Exceptions to the Octet Rule • 4.9 The Lengths and Strengths of Covalent Bonds © 2014 W. W. Norton Co.‚ Inc. 1 Chemical Bonds All chemical bonds consist of _______ that hold groups of atoms together and make them function as a unit. A bond will form if the energy of the aggregate is ______than that of the separated atoms. ____________ – energy required
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flammable; do not use near an open flame. Wear chemical splash goggles‚ chemical-resistant gloves‚ and a chemical-resistant apron. Please review current Material Safety Data Sheets for addi-tional safety‚ handling‚ and disposal information. Procedure: 1. Place the two halves of a Petri dish on the projection stage of an overhead projector. Pour enough sodium sulfate solution into each half of the Petri dish to just cover the bottom of each half dish. 2. Add 2–3 mL of universal indicator to
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Significant Figures are very important when reporting scientific data because they give us knowledge of how well we can actually measure data. Before getting into the calculations we must first understand the rules for counting significant figures. 1. All nonzero digits are significant. Example: 547 (3 sig. figs.) 2. Zeros in a number between non-zero digits are always significant. Example: 4308 (4 sig. figs.) 3. Trailing zeros to the right of a decimal point are significant. Example: 4
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performed several electrical discharges over a mixture of potassium hydroxide. By this process‚ he converted nitrogen of the air into potassium nitrate. Then‚ he removed the oxygen excess‚ but there still remained a small amount of gas‚ no larger than 1/120 of the original volume of air. He considered that this difference had been caused by experimental errors. About 100 years later‚ Lord Rayleigh and Sir William Ramsey discover Argon in 1894. For Ramsey‚ it is was as early as 1885-1890 when he published
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(molecule or ion) that is able to lose‚ or "donate" a hydrogen ion (proton)‚ and a base is a species with the ability to gain or "accept" a hydrogen ion (proton). acid salt: NaHSO4 & H2O => Na+ & H3O+ & SO4-2 basic salt: Na2CO3 & H2O => 2Na+ & (HCO3)-1 & OH- neutral salt: NaCl & H2O => Na+ & Cl- & H2O Module 5- Buffers 15. An acid contributes a surplus of hydrogen ions to a solution. A base contributes a surplus of hydroxide (OH) ions to a solution. 16. Buffer solutions are solutions that resist
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Name Naza Moore ID# 24120389 Lab# 2 Lab instructors Alecia Palmer and Donald Burke Course Instructor Maureen Wilson Lab Title Preparation of cyclohexene from cyclohexanol Aim Preparation of an Alkene by dehydration of an alcohol in the presence of a catalyst. Calculate the percentage recovery of products. Test for purity and identification of products. Abstract Cyclohexene and cyclohexanol are both colourless aromatic compounds. The major difference between the two is the presence
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Atmospheric chemistry is a branch of atmospheric science in which the chemistry of the Earth’s atmosphere and that of other planets is studied. Environmental chemistry is the scientific study of the chemical and biochemical phenomena that occur in natural places. It can be defined as the study of the sources‚ reactions‚ transport‚ effects‚ and fates of chemical species in the air‚ soil‚ and water environments; and the effect of human activity on these. Environmental chemistry is an interdisciplinary
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then the substance conducted electricity. The two ends of the probe were held away from each other in the dissolved form of the substance and if the light flashed on‚ then the substance conducted electricity when dissolved. I think substance 1 is a covalent compound. This is because it had a low melting point during the melting point test. Substance 2 might be a metallic compound because it had a high melting point but also low solubility in water. I think substance 3 is an ionic compound
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Where Could New Americans Turn for Help? Major problems for immigrants who traveled to America in the late 19th and early 20th centuries occurred. Newcomers to U.S. cities had few or no skills to perform any job in the American economy‚ could not speak English‚ and much more. One social problem that I would like to address is that of housing and feeding immigrants if they came to America with no money. I would like to help immigrants who come to America with no money‚ a large family‚ and no real
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