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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Hanna Rich 2/25/14 Chemistry 1110 Chemistry in the News Wireless Cardiac Defibrillator The heart is an incredible muscle. Unlike the brain where a person can continue to be “alive” without any electrical activity‚ without a heartbeat‚ a person cannot live. The average person doesn’t ever think about how or why their hearts lub dub every minute of every day until they die. For someone whose heart doesn’t beat properly‚ the lub dub is a frequent worry. Brandon England is one of those people
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Chemistry vacation Assignment Standard -X 1. Name a sodium compound which is used for softening hard water 2. Write the chemical name and formula of baking soda? 3. What will happen if the solution of sodium hydrogen carbonate is heated? Give the equations of the reaction involved? 4. Write the chemical name and the formula of bleaching powder. 5. Write the chemical formula of plaster of Paris? 6. What will happen if heating is not controlled while preparing
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Clare Chong P2 ! ! ! ! ! Chemistry Practical 4: Measuring rate of reaction Aim of experiment: To determine the rate of reaction when the concentration of I2 increases. ! ! ! Chemical equation: 2Fe3+ + 2I- --> 2Fe2+ + I2 ! ! ! Apparatus & materials: Apparatus Quantity 50ml Pipette 1 10ml Pipette 1 Pipette bulb 1 100ml beaker 2 50ml Burette 1 250ml Conical Flask 6 Timer 1 Distilled water 100ml or more 50ml Measuring
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The Chemistry of Toothpaste Toothpaste is not a new thing. It has been traced back to Ancient Egypt. They used a powdered rock and vinegar‚ which created a chemical reaction that dissolves the plaque on teeth. In 1900’s people used hydrogen peroxide and baking soda or chalk‚ pulverised brisk and salt as a toothpaste. Toothpastes today‚ are mostly made up of abrasives‚ surfactants‚ a detergent‚ a thickener‚ a moisturizer‚ water‚ flavouring agents‚ coloring‚ sweeteners‚ fluoride and desensitizers
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Major Chemistry questions: 1. Analyse the progress in the development and use of a named bioploymer. This anslysis should name the specific enzyme(s) used or organism used to synthesise the material and an evaluation of the use or potential use of the polymer produced related to it’s properties. Polyhydroxybutanoate (PHB) Progress Analysis: - Bacteria first used to make PHB in 1925 at Pastuer Institute in Paris. - In 1970’s adopted by Imperial Chemical Industries (ICI) – Alcaligenes
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Name: Shahid Hussain Subject: Chemistry Teacher: Dr Ramani Topic: Comparing Solutions Saturated Solutions | A solution that can hold no more of the solute at a particular temperature is said to be a saturated solution at that temperature. | When someone adds sugar to iced tea‚ the sugar disappears. If you add one teaspoon of sugar to iced tea‚ you get an unsaturated solution. If you keep
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The chemistry of hairspray What is hairspray: introduction Hair spray (or hair lacquer) is a common household aqueous solution that is used to keep hair stiff or in a certain style. Weaker than hair gel‚ hair wax‚ or glue‚ it is sprayed to hold styles for a short period of time. Using a pump or aerosol spray nozzle it sprays evenly over the hair. Hairspray was first developed and manufactured in 1948 by Chase Products Company‚ based in Broadview‚ Illinois.Its active ingredient is a suitable
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Chemistry Notes Cracking: * 2 types of Cracking; Catalytic cracking and Steam/thermal cracking. * Catalytic cracking‚ using a catalyst called Zeolite (Aluminosilicate)‚ 500 degrees C‚ in the absence of air and at pressures just above atmospheric * Thermal cracking is done without a catalyst; steam is passed through very hot metal tubes at 700-1000 degrees C at just above atmospheric pressure. * This is used to break down longer chains of unsalable hydrocarbons into smaller salable
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Chemistry in Photography Background A photograph is an image made by a photo-chemical reaction which records the impression of light on a surface coated with silver atoms. The reaction is possible due to the light-sensitive properties of silver halide crystals. Equation form for silver halides: Ag + + e - Ag Species produced include: Ag2+‚ Ag2o‚ Ag3+‚ Ag3o‚ Ag4+‚ Ag4o In 1556‚ the alchemist Fabricius was the first to discover that light can photochemically react with these crystals to
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