...Atoms, Molecules and Ions. AN ATOM is the smallest particle of an element. They cannot be split into smaller particles in chemical reactions. Iron is made of iron atoms (Fe). Sulphur is made of sulphur atoms (S) A MOLECULE is a small group of atoms joined together. The atoms may be the same (e.g. O2) or different (e.g. H2O). The chemical formula shows the number and type of atoms present. Non-metal compounds are made of molecules: Carbon dioxide contains CO2 molecules Methane (natural gas) contains CH4 molecules AN ION is an atom or group of atoms with an electrical charge (+ or -). Metal compounds such as sodium chloride or copper sulphate contain ions. Sodium chloride is made of Na+ and Cl- ions Copper Sulphate is made of Cu2+ and SO42- ions Note that metals form positive ions while non-metals form negative ions. A solid is represented by (s). e.g. H2O(s) is ice. A liquid is represented by (l) e.g. Fe(l) is molten iron. A gas is represented by (g) e.g. H2O(g) is steam. A solution in water is represented by (aq). Salt dissolved in water is NaCl(aq). You should remember that the common gases are diatomic (have 2 atoms in each molecule). These are Oxygen O2; Hydrogen H2; Nitrogen N2; and Chlorine Cl2. Elementary Particles Atoms are made up of smaller particles called protons, neutrons and electrons. The protons and neutrons cluster together in a small nucleus at the centre of the atom while the electrons orbit the nucleus. The main properties...
Words: 5119 - Pages: 21
...document/publication should be sent to us at enquiries@educationscotland.gov.uk. This document is also available from our website at www.educationscotland.gov.uk. Contents Introduction 5 Chemical analysis 6 Qualitative and quantitative analysis 6 Volumetric analysis 6 Gravimetric analysis 14 Colorimetric analysis 17 Organic techniques 22 Introduction 22 Preparation 22 Isolation 24 Purification 29 Identification 33 Percentage yield 37 Errors 39 Accuracy and precision 39 Repeatability and reproducibility 41 Quantifying errors 41 Absolute uncertainties and percentage uncertainties 42 Combining uncertainties 43 Some ‘forgotten’ uncertainties 46 Experiments 53 Experiment 1A: Preparation of a standard solution of 0.1 mol l–1 oxalic acid 53 Experiment 1B: Standardisation of approximately 0.1 mol l–1 sodium hydroxide 55 Experiment 1C: Determination of the ethanoic acid...
Words: 26805 - Pages: 108
...document/publication should be sent to us at enquiries@educationscotland.gov.uk. This document is also available from our website at www.educationscotland.gov.uk. Contents Introduction 5 Chemical analysis 6 Qualitative and quantitative analysis 6 Volumetric analysis 6 Gravimetric analysis 14 Colorimetric analysis 17 Organic techniques 22 Introduction 22 Preparation 22 Isolation 24 Purification 29 Identification 33 Percentage yield 37 Errors 39 Accuracy and precision 39 Repeatability and reproducibility 41 Quantifying errors 41 Absolute uncertainties and percentage uncertainties 42 Combining uncertainties 43 Some ‘forgotten’ uncertainties 46 Experiments 53 Experiment 1A: Preparation of a standard solution of 0.1 mol l–1 oxalic acid 53 Experiment 1B: Standardisation...
Words: 4104 - Pages: 17
...Chem Notes Unit 1: Quantitative Chemistry, Measurement and Data Processing Unit Conversions: dm3 (decimeter^3) = L (liters) cm3 (centimeter^3) = mL (milliliters) 0 ° C (degrees celsius) = 273.15 K (Kelvin) convert Celsius into Kelvin by adding 273.15 to the current value The difference between Accuracy and Precision: Accuracy → difference between average of measured values and true value Precision → the reproducibility of the measurements, how close they are to eachother Types of Error: Systematic Error → fundamental flaws in equipment, observer. Leads to values all higher or lower than actual value. High precision, low accuracy. Random Error → uncertainty in measurement devices. Leads to random variation in values. Always occurs and can generally not be improved. Precise measurements have low random error. Accurate measurements have low systematic error and generally low random error. Uncertainties: Graduated/Analog Device → ±1/2 of the smallest increment on the device. Digital Device → ±1 on the last digit the device records (it estimates for you.) Exact Values → No uncertainty. For all uncertainties the recorded value MUST be to the same decimal place as the uncertainty. Change your final answer's significant digits if necessary. Uncertainties should be rounded to ONE digit. Propagation of Uncertainties: Addition and Subtraction → Add uncertainties. Multiplication and Division → Calculate Relative Uncertainty by dividing...
Words: 4509 - Pages: 19
...Experiment : Title : Objective : 1 Preparation of standard solution and standardization of hydrochloric acid To prepare a standard solution of sodium carbonate and use it to standardize a given solution of dilute hydrochloric acid. Anhydrous sodium carbonate is a suitable chemical for preparing a standard solution (as a primary standard). The molarity of the given hydrochloric acid can be found by titrating it against the standard sodium carbonate solution prepared. The equation for the complete neutralization of sodium carbonate with dilute hydrochloric acid is Na2CO3(aq) + 2HCl(aq) → 2NaCl(aq) + CO2(g) + H2O(l) The end-point is marked by using methyl orange as indicator. Introduction : Chemicals : Apparatus : Procedure : solid sodium carbonate, 0.1 M hydrochloric acid 1. 2. 3. 4. 5. 6. 7. 8. Weight out about 1.3 g of anhydrous sodium carbonate accurately using the method of “weighing by difference”. Transfer the weighed carbonate to a beaker and add about 100 cm3 of distilled water to dissolve it completely. After dissolving, transfer the solution to a 250.00 cm3 volumetric flask. Rinse the beaker thoroughly and transfer all the washes into the volumetric flask. Remember not to overshoot the graduation mark of the flask. Make up the solution to the mark on the neck by adding water. Pipette 25.00 cm3 of sodium carbonate solution to a clean conical flask. Add 2 drops of methyl orange indicator to the carbonate solution. Titrate the carbonate solution with the...
Words: 8885 - Pages: 36
...physical and chemical processes; • state the law of equilibrium; • explain characteristics of equilibria involved in physical and chemical processes; • write expressions for equilibrium constants; • establish a relationship between Kp and K c ; • explain various factors that affect the equilibrium state of a reaction; • classify substances as acids or bases according to Arrhenius, Bronsted-Lowry and Lewis concepts; • classify acids and bases as weak or strong in terms of their ionization constants; • explain the dependence of degree of ionization on concentration of the electrolyte and that of the common ion; • describe pH scale for representing hydrogen ion concentration; • explain ionisation of water and its duel role as acid and base; • describe ionic product (Kw ) and pKw for water; • appreciate use of buffer solutions; • calculate solubility product constant. Chemical equilibria are important in numerous biological and environmental processes. For example, equilibria involving O2 molecules and the protein hemoglobin play a crucial role in the transport and delivery of O2 from our lungs to our muscles. Similar equilibria involving CO molecules and hemoglobin account for the toxicity of CO. When a liquid evaporates in a closed container, molecules with relatively higher kinetic energy escape the liquid surface into the vapour phase and number of liquid molecules from the vapour phase strike the liquid surface and are retained in the liquid phase. It gives rise to a constant...
Words: 16204 - Pages: 65
...CARIBBEAN EXAMINATIONS COUNCIL Caribbean Secondary Education Certificate CSEC® CHEMISTRY SYLLABUS Effective for examinations from May–June 2015 CXC 21/G/SYLL 13 Published by the Caribbean Examinations Council. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form, or by any means electronic, photocopying, recording or otherwise without prior permission of the author or publisher. Correspondence related to the syllabus should be addressed to: The Pro-Registrar Caribbean Examinations Council Caenwood Centre 37 Arnold Road, Kingston 5, Jamaica Telephone Number: + 1 (876) 630-5200 Facsimile Number: + 1 (876) 967-4972 E-mail Address: cxcwzo@cxc.org Website: www.cxc.org Copyright © 2013 by Caribbean Examinations Council The Garrison, St Michael BB14038, Barbados CXC 21/G/SYLL 13 Contents RATIONALE ................................................................................................................................... AIMS ............................................................................................................................................. CANDIDATE POPULATION ............................................................................................................. SUGGESTED TIME-TABLE ALLOCATION ........................................................................................ ORGANISATION OF THE SYLLABUS .................................................
Words: 24316 - Pages: 98
...1 UTME 2001 Type R Questions Use the graph below to answer questions 1 and 2. 100 200 Time (mins) T(0C) 0 1 2 3 4 5 6 7 8 300 Liquid Vapour Solid 1. If the gas is cooled, at what temperature will it start to condense? (A) 1250C (B) 1500C (C) 1750C (D) 2500C 2. How long does it take all the solid to melt? (A) 2.5 mins (B) 6.0 mins (C) 1.0 mins (D) 3.0 mins 3. 25cm3 of a gas X contains Z molecules at 150C and 75mmHg. How many molecules will 25cm3 of another gas Y contain at the same temperature and pressure? (A) 2Y (B) 2Z (C) Z (D) Y 4. What mass of water is produced when 8.0g of hydrogen reacts with excess oxygen? (A) 36.0g (B) 8.0g (C) 72.0g (D) 16.0g [H = 1, O = 16] 5. A particle that contains 9 protons, 10 neutrons and 10 electrons is a (A) negative ion (B) positive ion (C) neutral atom of a non metal (D) neutral atom of a metal 6. Cancerous growth are cured by exposure to (A) γ -rays (B) β -rays (C) α -rays (D) x-rays 7. An oxide XO2 has a vapour density of 32. What is the atomic mass of X (A) 32 (B) 20 (C) 14 (D) 12 [O = 16] 8. Milikan’s contribution to the development of atomic theory is the determination of (A) charge on electron (B) positive rays (C) charge to mass ratio (D) cathode rays 9. Four elements W, X, Y, and Z have atomic numbers 2, 6, 16 and 20 respectively. Which of these elements is a metal? (A) X (B) W (C) Z (D) Y 10. An element X with relative atomic mass 16.2 contains two isotopes 16X 8 with relative abundance of 90% and X m8 with relative abundance of 10%...
Words: 17166 - Pages: 69
...Abstract The aim of the Project is to find out the geo-engineering properties of fly ash, which can act as a stabilizer to many soils in geo-engineering field. The project describes the use of local fly ash in construction industry in a way to minimize the industrial waste. Their been serious shortage of natural material, which are used in Highway or Earth dam construction. Due to soil excavation, deforestation occurs which affects the bio-diversity. Industrial waste such as fly-ash, slag etc can be effectively used in soil stabilization. Several geo engineering Labrotory experiments were performed on fly ash to determine its properties, which may be used in road construction, earth dam construction, soil stabilization etc. If these materials can be used in highway or dam construction, it will be a great effort in minimizing the industrial pollution. Fly ash was collected from captive power plant from the dump pad of Rourkela steel plant. These are stored in air tight container after being oven-dried. Experiments such as determination of compaction properties, CBR analysis, Un-confined compressive strength test, permeability etc are done in order to determine the geo-engineering properties of fly ash, which can taken account in the construction field. A brief comparison is made between fly ash and other soil properties which are used as sub-grade, base in Highway construction. Introduction Electricity is the key for development of any country. Coal is a major source of...
Words: 11302 - Pages: 46
...Year 11 Science Mentoring Task Booklet Things to remember when answering 6 mark exam questions: 1. 2. 3. 4. 5. 6. Try and remember everything you can about what the question is asking before you start answering it Make at least 6 points Write in full sentences starting with capital letters and ending with full stops Try and answer the question in around five minutes Check your answer to make sure you have not left anything out Remember to use key words when appropriate Things to remember when marking 6 mark exam questions: 1. 2. 3. 4. Use a green pen Read through the science points at the bottom of the mark scheme first In the answer put ticks to show where the marks are coming from Mark for spelling and grammar by circling the word or part of the text and writing above it as follows: • • • • 5. 6. 7. 8. Spelling mistake (Sp) Missing full stop (Gr) Missing capital letter (Gr) Poor grammar (Gr) Cross out any bits that are irrelevant to the question Add up their total number of marks If there are more than three spelling or grammar errors minus one mark Leave constructive feedback Biology Cells Tissues & Organs Summary All living things are made up of cells. The structures of different types of cells are related to their functions. To get into or out of cells, dissolved substances have to cross the cell membranes. Cells Cells are the smallest unit of life. All living things are made of cells. Most human cells, like most other animal cells, have the following...
Words: 18368 - Pages: 74
...Added to this was a reduction in availability of the traditional resources to supply the increasing world population. Chemists and chemical engineers continue to play a pivotal role in the search for new sources of traditional materials such as those from the petrochemical industry. As the fossil organic reserves dwindle, new sources of the organic chemicals presently used have to be found. In addition, chemists are continually searching for compounds to be used in the design and production of new materials to replace those that have been deemed no longer satisfactory for needs. This module increases students’ understanding of the implications of chemistry for society and the environment and the current issues, research and developments in chemistry. 1.1 Construct word and balanced formulae equations of all chemical reactions as they are encountered in this module: • Acid reactions: o acid (aq) + base (aq) salt (aq) + water (l) o acid (aq) + active metal (s) salt (aq) + hydrogen (g) o acid (aq) + metal carbonate (s) salt (aq) + water (l) + carbon dioxide (g) • Cracking of long chain alkanes (e.g. decane) to give a shorter chain alkene & alkane o Thermal cracking (heated with steam in absence of O2 to 750-900°C) Initiation: C10H22 2C5H11· Propagation: C5H11· C3H7· + C2H4 Termination: 2C3H7· C6H14 o Catalytic cracking zeolite (heated in absence of O2 to 500°C)...
Words: 34562 - Pages: 139
...CHAPTER ONE INTRODUCTION 1.1 BACKGROUND OF STUDY Removal of heavy metals such as cadmium, lead, nickel, chromium and copper from aqueous solution is necessary because of the hazardous effect it does on the environment ,thereby making environmental protection important, however waste solutions containing heavy metal elements need treatment systems that can remove these contaminants effectively (Harvey and Chantawong, 2001). Frequent appearance of these metals in waste streams from many industries, including electroplating, metal finishing, metallurgical, tannery, chemical manufacturing, mining and battery manufacturing. This problem has received considerable attention in recent years, primarily due to the concern that those heavy metals in waste streams can be readily adsorbed by marine animals and directly enter the human food chain, thus presenting a high health risk to consumers (Lin et al., 2000). A number of technologies for treating contaminated effluents have been developed over the years. The most important of these techniques include chemical precipitation, filtration, ion- exchange, reverse osmosis and membrane systems. However, all these techniques have their inherent advantages and limitations in application. In the last few years, adsorption has been shown to be an alternative method for removing dissolved metal ions from liquid wastes (Bayat, 2002). The removal of heavy metal ions from industrial wastes using different adsorbents is currently...
Words: 9309 - Pages: 38
...efficiency of bacteria has been optimized. Biodegradation of methylene blue and bromophenol blue was demonstrated by monitoring the effects of the different parameters and determining optimal conditions for degradation activity. Introduction Several industrial activities, such as textile dyeing, olive oil extraction and the manufacture of pulp and paper are characterized by intensive water consumption rates. They release huge amounts of more or less coloured effluents into the environment. As far as synthetic dye release is concerned, textile dyeing facilities and the manufacture of dyestuffs are two major polluting sources. In addition, traditional textile dyeing processes generate a large amount of coloured effluents, because about 100 litres of water are required to process 1 kg of dyed fabrics. Moreover, up to 15% of applied dyestuffs are lost to the effluents due to dyeing process inefficiencies. Colour itself could be very pernicious to the receiving water courses not only for aesthetic reasons and toxicity towards many aquatic organisms, but also because coloured compounds reduce water transparency, which, in turn, affects photosynthetic activity, thus causing severe damage to the ecosystems. (Nermeen and...
Words: 6765 - Pages: 28
...Chemistry Modern Analytical Chemistry David Harvey DePauw University Boston Burr Ridge, IL Dubuque, IA Madison, WI New York San Francisco St. Louis Bangkok Bogotá Caracas Lisbon London Madrid Mexico City Milan New Delhi Seoul Singapore Sydney Taipei Toronto McGraw-Hill Higher Education A Division of The McGraw-Hill Companies MODERN ANALYTICAL CHEMISTRY Copyright © 2000 by The McGraw-Hill Companies, Inc. All rights reserved. Printed in the United States of America. Except as permitted under the United States Copyright Act of 1976, no part of this publication may be reproduced or distributed in any form or by any means, or stored in a data base or retrieval system, without the prior written permission of the publisher. This book is printed on acid-free paper. 1 2 3 4 5 6 7 8 9 0 KGP/KGP 0 9 8 7 6 5 4 3 2 1 0 ISBN 0–07–237547–7 Vice president and editorial director: Kevin T. Kane Publisher: James M. Smith Sponsoring editor: Kent A. Peterson Editorial assistant: Jennifer L. Bensink Developmental editor: Shirley R. Oberbroeckling Senior marketing manager: Martin J. Lange Senior project manager: Jayne Klein Production supervisor: Laura Fuller Coordinator of freelance design: Michelle D. Whitaker Senior photo research coordinator: Lori Hancock Senior supplement coordinator: Audrey A. Reiter Compositor: Shepherd, Inc. Typeface: 10/12 Minion Printer: Quebecor Printing Book Group/Kingsport Freelance cover/interior designer: Elise Lansdon Cover image: © George Diebold/The...
Words: 88362 - Pages: 354
...living things change from one form to another. The human body contains chemical compounds, such as water, carbohydrates (sugar, starch, and fiber), amino acids (in proteins), fatty acids (in lipids), and nucleic acids (DNA and RNA). These compounds in turn consist of elements such as carbon, hydrogen, oxygen, nitrogen, phosphorus, calcium, iron, zinc, magnesium, manganese, and so on. All of these chemical compounds and elements occur in various forms and combinations (e.g. hormones, vitamins, phospholipids, hydroxyapatite), both in the human body and in the plant and animal organisms that humans eat. The human body consists of elements and compounds ingested, digested, absorbed, and circulated through the bloodstream to feed the cells of the body. Except in the unborn fetus, the digestive system is the first system involved in obtaining nutrition. In a typical adult, about seven liters of digestive juices enter the digestive tract.[citation needed] These break chemical bonds in ingested molecules, and modulate their conformations and energy states. Though some molecules are absorbed into the bloodstream unchanged, digestive processes release them from the matrix of foods. Unabsorbed matter, along with some waste products of metabolism[examples needed], is eliminated from the body in the feces. Studies of nutritional status must take into account the state of the body before and after experiments, as well as the chemical composition of the whole diet and of all material excreted and...
Words: 8834 - Pages: 36
