MARKING SCHEME PAPER 2 4541/2 http://cikguadura.wordpress.com © Trial2011 Hak Cipta Sekolah Berasrama Penuh SULIT SULIT 2 MARKING SCHEME FOR CHEMISTRY PAPER 2 4541/2 No. 1. (a) (i) (ii) Answer Zinc Mark 1 1 1 1 1 1 1. The presence of X/zinc atoms disrupts the orderly arrangements of copper atoms 2. This reduce the layers of atoms from sliding over one another easily Steel Silicon dioxide/silica /sand Heat resistant/can withstand with high temperature (iii) (b)(i) (ii) (c) (i) H Cl | |
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until a precipitate formed. All observations were recorded. Then‚ 10 drops of nitrate solution and 10 drops of 6 M NaOH were mixed together in a centrifuge tube‚ then the mixture was transferred to a dry centrifuge tube with a pipet. A few granules of zinc was added to the centrifuge tube and it was heated for 2 minutes before the Zn started to break down and gas started to be emitted. A piece of red litmus paper was creased into a V and wetted and was placed into the top of the tube. The paper turned
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Corrosion Let metal sit surrounded by oxygen for a while and the metal will corrode. Corrosion is the chemical reaction that takes place when a metal is in contact with oxygen. The metal reacts with the oxygen to form a compound called an oxide on the surface of the metal. The metal becomes tarnished and loses its shine. Metals high in the reactivity series (an observable series of metals‚ in order of reactivity from highest to lowest) corrode more quickly than less reactive metals
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Pennies may have been practical several years ago; however‚ now they are inconvenient and obsolete. As an American citizen who pays with U.S. currency almost every day and almost every day‚ inconvenienced by the use of pennies. Pennies make even less sense provided the fact that the United States Government has made such a large amount of pennies that the materials used to make pennies are worth more than a penny itself. Other countries have already done this and it is working out well for them‚
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resistant pad • Litmus paper • Pipets • Spatula • Test tubes Materials: Ammonium carbonate‚ 0.5g Calcium carbonate‚ 0.5g Copper chloride solution‚ 4mL Hydrochloric acid‚ 4mL Magnesium ribbon‚ 2-4 cm strips Phenolphthalein indicator‚ 1 drop Sodium hydroxide solution‚ 1mL Sodium phosphate solution‚ 1mL Water Zinc‚ mossy‚ or zinc shot‚ 1-2 pieces Introduction: In this lab we will classify different chemical reactions. Classifying chemical reactions allows us to
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UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education *1144188971* COMBINED SCIENCE Paper 2 (Core) 0653/21 October/November 2010 1 hour 15 minutes Candidates answer on the Question Paper. No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your Centre number‚ candidate number and name on all the work you hand in. Write in dark blue or black pen. You may use a soft pencil for any diagrams‚ graphs‚ tables or rough working
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strips that are stained with dark‚ reddishbrown stuff. Part II: Decomposition of hydrogen peroxide Appearance of potato and hydrogen peroxide combination: Lots of white‚ foamy bubbles around the potato slices. Day 2 Observations: Part III: Reaction between zinc and acetic acid Appearance of penny in vinegar after 30 minutes: Pretty dark coloured. Quite hard to see Lincoln’s head or the Memorial. Part IV: Reaction between baking soda and vinegar Description of what happened when the baking soda and vinegar were combined Immediately
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There are 18 data sets that accompany the text book. These data sets can be found when you enter StatCrunch from the course. Here is a list of the data sets and the variables found in those data sets. If there is no listing of variables then they are easily identified in the data set. Data Set 1: Health Exam Results (both male and female) AGE is in years‚ HT is height (inches)‚ WT is weight (pounds)‚ WAIST is circumference (cm)‚ PULSE is pulse rate (beats per minute)‚ SYS is systolic blood pressure
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your observations. Gather the following lab equipment: Goggles‚ test tubes‚ 24 well plate‚ Gas assembly with copper and plastic tubing and a #00 stopper‚ short stem pipet‚ rubber stopper #00 with one hole and a pipet tip with plastic gas delivery tube‚ 2 small tables of AlkaSeltzer‚ 4mL Bromothymol blue .04%‚ 20 mL hydrochloric acid‚ 4-6 pieces of manganese metal‚ 4-6 pieces of mossy zinc‚ and 3 pipet bulbs. Gather the following items: Matches‚ toothpicks‚ pie tin‚ white vinegar‚ 3% hydrogen peroxide
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What chemical compounds does the human body consist of? Oxygen (65%) and hydrogen (10%) are predominantly found in water‚ which makes up about 60 percent of the body by weight. It’s practically impossible to imagine life without water. Carbon (18%) is synonymous with life. Its central role is due to the fact that it has four bonding sites that allow for the building of long‚ complex chains of molecules. Moreover‚ carbon bonds can be formed and broken with a modest amount of energy‚ allowing
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