Education Higher Tier January 2012 1 2 3 4 5 TOTAL Science B Unit Chemistry C1 CHY1H Chemistry Written Paper Unit Chemistry C1 H Thursday 26 January 2012 You will need no other materials. You may use a calculator. 9.00 am to 9.45 am Time allowed 45 minutes Instructions Use black ink or black ball-point pen. Fill in the boxes at the top of this page. Answer all questions. You must answer the questions in the spaces provided. Do not write outside the box around
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A. Role of Chemistry in Society Applications of chemical science have contributed significantly to the advancement of human civilization (1‚ 2‚ 3). With a growing understanding and ability to manipulate chemical molecules‚ the post-World War II chemist was considered a societal problem solver. They synthesized crop-enhancing agricultural chemicals to ensure a constant and viable food supply. They played a significant role in the eradication of deadly diseases by developing life-saving pharmaceuticals
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Chemistry and Us The world is surrounded by so many things and everything is made of chemicals. Chemistry is very vital because it helps us to know the composition and changes of matter. Every single day of our life passes through chemistry in many ways. Human body works through the chemical reactions happening inside it. When we breathe‚ eat and sleep there’s still the presence of chemistry. The oxygen and foods we take helps our body to work. Exchanges of gasses‚ breaking down of foods we
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CHM 256: BASIC ANALYTICAL CHEMISTRY TUTORIAL 1: INTRODUCTION: ANALYTICAL CHEMISTRY 1. What is chemical analysis? 2. Differentiate between qualitative and quantitative analysis (Oct 2008‚ 2009‚ Dec 2009‚ Apr 2010) 3. Give 7 steps in performing any chemical analysis (Apr 2010) 4. Briefly explain how to prepare the following solutions: a) 1.0 L 10.50 % (w/v) aqueous CH3CH2CH2OH (answer : 105 g) (Oct 2006‚ Oct 2007‚ Oct 2008) b) 500 mL 2.0 M H2SO4 from a commercial reagent‚ at 90% (w/w) purity
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Chemistry and Society CHM/110 Xavier Villarreal November 6‚ 2011 Chemistry is a vast quantity of a person’s everyday life. A person can find chemistry in his or her daily life in the foods that a person eats‚ air a person breathes‚ soap‚ and accurately everything a person comes in contact with. Chemistry is significant in everyday life because chemicals make up everything in life. For example‚ a person’s body‚ pet‚ a desk‚ the sun‚ food‚ and drugs a person may take‚ to name a few. A person
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De Leon‚ Mary Joy P. #10 January 7‚ 2014 BSA 3-14 ACCO 3116 Prof. Flora Briones Chapter 20 SUBSTANTIVE TESTS OF TRANSACTIONS AND BALANCES 1. What is a cutoff bank statement? How is it used by the auditor? Cut off bank statement is the statement of transactions occurred for the 7 to 14 consequent days from the closing date of financial statement like Dec 31 provided by banks. It is used by the auditors to check the accuracy of checks outstanding and deposits in transit in accounting
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Chemistry 12 Unit 1 - Reaction Kinetics Chemistry 12 Worksheet 1-3 - Reaction Mechanisms 1. It is known that compounds called chlorofluorocarbons (C.F.C.s) (eg. CFCl3) will break up in the presence of ultraviolet radiation‚ such as found in the upper atmosphere‚ forming single chlorine atoms: CFCl3 CFCl2 + Cl The Cl atoms then react with Ozone (O3) as outlined in the following mechanism. Step 1: Step 2: Cl + O3 ClO + O2 ClO + O Cl + O2 (single "O" atoms occur naturally in the atmosphere
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Module 4: 10. Strong Bases: NaOH‚ KOH‚ Na2CO3‚ NaHCO3‚ Na3PO4‚ NaHPO4‚ Strong Acids: Fe(NO3)3‚ HCL‚ HNO3‚ Al(NO3)3‚ NiCl2‚ H2SO4 11. Acidic Neutral Basic NaCl KNO3 NaOH HC2H3O2 Na2CO3 NaC2H3O2 NaHCO3 Fe(NO3)3 NaNO3 Na3PO4 HCl MgSO4 KOH HNO3 Na2SO4 NaHPO4 CuSO4 NaNO2 CoCl2 Al(NO3)3 NiCl2 H2SO4 KCl NH4Cl 12. CuSO4 CuCO3.Cu(OH)2(s) + 2 H2SO4(aq) ----> 2 CuSO4(aq) + CO2(g) + 3 H2O(l) Na3PO4 Na3PO4 (aq) + 3H2O (l) --> H3PO4 (aq) + 3NaOH
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Experiment 9 : The effect of substrate concentration on enzyme activity Objective To find out the relationship between the substrate concentration and the rate of reaction by determining the number of bubbles produce Hydrogen peroxide (H2O2) is a by-product of biochemical metabolism. An accumulation of hydrogen peroxide can be deadly‚ so it has to be decomposed. One of the decomposing factors is an enzyme called Catalase. Catalase breaks hydrogen peroxide into water and oxygen. The chemical
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Properties of Different Bonds An ionic compound forms from a nonmetal and metal element. A covalent compound is formed by two non metal elements. A metallic compound is formed by two metal elements. Metallic compounds have generally high melting points‚ are loose and flexible with their electrons‚ conduct electricity well‚ and have low solubility in water. Ionic compounds are generally crystals‚ have a high melting point‚ and usually have high solubility in water and conduct electricity well when
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