the element with the least electronegativity is: (A) Lithium (B) Carbon (C) Boron (D) Fluorine (ii) Identify the statement which does not describe the property of alkenes: (A) They are unsaturated hydrocarbons (B) They decolourise bromine water (C) They can undergo addition as well as substitution reactions (D) They undergo combustion with oxygen forming carbon dioxide and water. (iii) This is not an alloy of copper: (A) Brass (B) Bronze (C) Solder (D) Duralumin. www.topperlearning.com 1 ICSE X
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1. Which of the following polyatomic ions have a 3-ionic charge? a. Phosphate b. Hydrogen carbonate c. Sulfate d. Hydroxide e. Nitrate 2. In which of the following is the metric unit paired with its correct abbreviation? a. Centimeter/km b. Kilogram/cg c. Millimeter/mL d. Microgram/mg e. Gram/gm 3. The number of electrons in an ion with 20 protons and an ionic charge of 2- is? a. 22 b. 18 c. 20 d. 16 e. 24 4. Which of the following is a measurement of mass in the metric system
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TWS Chemistry 1013-231 Organic Chemistry I Name___________________________________ 2011 Exam#2 - Version 2 MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Energy is __________ when bonds are formed and is __________ when bonds are broken; therefore‚ bond dissociation energies are always __________. A) consumed / released / endothermic B) consumed / released / isothermic C) released / consumed / endothermic D) consumed / released / exothermic
Free Chemical reaction Chlorine Organic chemistry
involves covalent bonds. Reduction reactions can be determined through three features. The first is a loss of oxygen from a bond or loss of a bond to oxygen as in the case of carbon-oxygen double bond to a carbon-oxygen single bond. The second is the addition of hydrogen to a bond and thirdly‚ the replacement of a more electronegative atom with carbon or hydrogen. In redox reactions‚ the reductant (or reducing agent) loses electrons and is oxidized while the oxidant (or oxidizing agent) gains electrons
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The Disappearing Spoon by Sam Kean‚ examines each of the elements on the periodic table. The Disappearing Spoon focuses on the history of the periodic table by recounting stories about each element on the table‚ and the scientist that discovered it. For each element‚ Kean provides an extensive backstory about its origin‚ the common (or uncommon) uses of the element‚ and other interesting tidbits. The author begins the novel with a general physical description of the periodic table as a whole; he
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(c) (CH3)2CHO- (d) (CH3)3CO- (Q.11) The correct order of decreasing dipole moment is: ( 1 mark ) (a) CH3Cl‚ CH3Br‚ CH3F (b) CH3Cl‚ CH3F‚ CH3Br (c) CH3Br‚ CH3Cl‚ CH3F (d) CH3Br‚ CH3F‚ CH3Cl (Q.12) HCl and HI do not give anti- markovnikov’s addition to alkenes in the presence of peroxides because: ( 1 mark ) (a) Both are highly ionic (b) One is oxidizing and other is reducing (c) One of the step is endothermic in both the cases (d) All the steps are exothermic in both the reactions.
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International Journal of Environmental Science and Development‚ Vol.2‚ No.1‚ February 2011 ISSN: 2010-0264 Ozone Layer Depletion and Its Effects: A Review Sivasakthivel.T and K.K.Siva Kumar Reddy Abstract - There are many situations where human activities have significant effects on the environment. Ozone layer damage is one of them. The objective of this paper is to review the origin‚ causes‚ mechanisms and bio effects of ozone layer depletion as well as the protective measures of this
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Great Lakes is currently the largest U.S. methyl bromide supplier in the U.S. producing more than 40 million pounds annually at their plants. Great Lakes Chemical ’s involvement in the bromine business has its roots in leaded gasoline. When tetraethyl lead (TEL) was invented as a gasoline additive back in the 1920s‚ it was found to leave a corrosive byproduct in the engine. Great Lakes developed international markets for its products. Globalization of leaded gasoline makes TEL responsible for nearly
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Writing Complete Equations Practice For each of the following problems‚ write complete chemical equations to describe the chemical process taking place. Important note: There are a few physical processes on this sheet – You can’t write an equation for a physical process! 1) When lithium hydroxide pellets are added to a solution of sulfuric acid (dihydrogen sulfate)‚ lithium sulfate and water are formed. 2) When dirty water is boiled for purification purposes‚ the temperature is brought up to
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<b>The Greenhouse Effect</b> <br>The earth’s climate is predicted to change because human activities are altering the chemical composition of the atmosphere through the build up of greenhouse gases primarily carbon dioxide‚ methane‚ and nitrous oxide. <br> <br>Energy from the sun drives the earth’s weather and climate‚ and heats the earth’s surface. This causes the earth to radiate the energy back into space. Atmospheric greenhouse gases (water vapour‚ carbon dioxide‚ and other gases) trap some
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