Introduction To Chemistry PDF

INTRODUCTION TO CHEMISTRY  Intended learning outcomes The students should be able to: Explain the significance of chemistry in the field of engineering Explain the scientific method Explain the three level of understanding/perspective in chemistry Describe properties of matter Classify m...

INTRODUCTION TO CHEMISTRY  Intended learning outcomes The students should be able to: Explain the significance of chemistry in the field of engineering Explain the scientific method Explain the three level of understanding/perspective in chemistry Describe properties of matter Classify matter into pure substances and mixture Compare solid, liquid and gas Accreditation Board for Engineering and Technology (ABET) A professional organization that oversees engineering education Defines ENGINEERING “Engineering is the profession in which the knowledge of mathematical and natural sciences gained by study, experience and practice is applied with judgement to develop ways to utilize economically the materials and forces of nature for the benefit of mankind.”  Definition of chemistry a branch of physical science, that deals with the study of the composition, properties and changes in matter Chemistry is sometimes called "the central science" because of its role in connecting the physical sciences, with the life sciences and applied sciences such as medicine and engineering Chemistry is an empirical science and is studied by: Measuring physical properties and  Significance of Chemistry Chemistry plays an important role in many areas of engineering and technology  Selection of materials and designs of structures (CE)  Essential in the understanding of how electrons flow as basis of electricity (ECE,EE)  Chemical reactions involve in the manufacturing of different products (food, beverages, pharmaceuticals, cosmetics, polymers, plastics, paints, etc) (CHE)  Experimental research and development of new products like drugs and alternative sources of energy  Design machines and other equipment (ME)  Solutions to environmental problems  Scientific method Chemistry as science employs scientific method A systematic approach to research Orderly and systematic approach to gather information in order to answer questions about the world Make observations of nature. Derive a hypothesis or build a model in response to observations. Construct experiments to bolster or refute hypothesis or model. Models in science Models refer to a largely empirical description. Gas pressure is proportional to temperature. Theories are explanations grounded in some more fundamental principle or assumption about the behavior of a system. Relationship between gas pressure and temperature explained using kinetic energy. MATTER AND ENERGY MATTER Anything that occupies space and has mass Stuff that makes up all the material things that are part of our lives Composed of tiny particles called atoms MASS vs WEIGHT MASS – a measure of quantity of matter WEIGHT- gravitational force of attraction exerted by the earth on a body Levels of Understanding/Perspective Macroscopic Microscopic Symbolic MACROSCOPIC PERSPECTIVE Matter is anything that has mass and can be observed. Matter is observed through their properties and MICROSCOPIC PERSPECTIVE Matter is composed of unimaginably small particles called atoms that retain the chemical identity of the element they represent. SYMBOLIC PERSPECTIVE Chemical Symbols are used to represent elements Chemical Formula is used to pure aluminum, represent Al compounds aluminum oxide, Chemical Al2O3 Equations are used to represent chemical reactions  PROPERTIES OF MATTER INTRINSIC PROPERTIES - inherent properties of substance - best identified matter - depend on the kind of material - permanent properties of substances - include taste, odor, color, melting point, boiling point, crystalline structure, viscosity, solubility, transparency, atomic or molecular diameter EXTRINSIC PROPERTIES -qualities that describe the outside appearance of matter - not characteristic of material itself - Example: size, shape, length and mass  MEASURABLE PROPERTIES EXTENSIVE PROPERTIES -depends on the amount of material present - Example: mass, length, volume INTENSIVE PROPERTIES -do not depend on the amount of material present - example: temperature, boiling point, melting point, density Physical and Chemical Properties PHYSICAL PROPERTIES -can be measured and observed without changing the composition or identity of substance CHEMICAL PROPERTIES -these properties are observed after a chemical change  STATES OF MATTER SOLID LIQUID GAS -Definite shape, rigid -Assume the shape of -Indefinite shape -Definite volume container -Indefinite volume -Particles are close -Definite volume -Particles are far apart together -Fluid- able to flow -Particles move fast -Particles can hardly -Particles are close -High kinetic energy move -Particles are mobile -Expands to fill the -Very low kinetic energy -Low kinetic energy container -High density -High density -Density depends on -Not affected by pressure -Less affected by pressure pressure CLASSIFICATION OF MATTER Images. Thinklink.com PURE SUBSTANCE  consist of only one type of matter  has a definite or constant composition  has a distinct properties  can not be separated by physical means  can be an ELEMENT OR COMPOUND  ELEMENT Composed of only one type of atom Fundamental substances from which all materials are constructed Simplest form of substance that can not be decomposed Can not be separated into simpler substance by chemical means 115 known elements Represented by SYMBOLS SYMBOLS OF ELEMENTS FROM LATIN WORDS Symbol Name Latin Word Na Sodium Natrium K Potassium Kalium Fe Iron Ferrum Cu Copper Cuprum Ag Silver Argentum Au Gold Aurum Hg Mercury Hydrargytum Pb Lead Plumbum Sb Antimony Stibium W Tungsten Wolfram  GROUPINGS OF ELEMENTS METALS SEMIMETALS NON-METALS -Brilliant luster -Metalloids -Light -Ductile (can be drawn -Propertiessimilar to -Powdery solid or into wire) both metals and non invisible gases at room -Malleable (can be metals temperature hammered into thin -Examples: Silicon, -Poor conductor of sheets) Boron, Arsenic electricity -Good conductor of heat Example: He, S, Ar and electricity - Examples: Cu, Al, Au, Ag  COMPOUNDS A substance composed of 2 or more elements chemically combined in definite and constant proportion A pure substance because all the particles in the compound are alike Elements that make up the compound lose their identity due to chemical change Can not be separated by ordinary physical means Molecules – particles that make up a compound COMPOUNDS Homogeneous entity where the elements have definite proportion by mass LAW OF DEFINITE PROPORTION OR COMPOSITION: any pure compound always contains the same elements in exactly the same proportion by mass Represented by CHEMICAL FORMULA COMPOUNDS ORGANIC COMPOUNDS - carbon containing compounds - Example: methane CH4 sucrose C12H22O11 ethyl alcohol CH3CH2OH - Exception: CaC2, MgCO3, KCN COMPOUNDS INORGANIC COMPOUNDS - compounds that do not contain carbon - Examples: NaCl H2O SO2 NaOH MIXTURE Physical combination of two or more substances in which the substances retain their distinct properties Do not have constant composition Can not be represented by chemical formula Can be separated by physical means Can be natural or artificial Can be homogeneous or heterogeneous Types of Mixture HOMOGENEOUS MIXTURE - has uniform appearance and composition - example is SOLUTION - Examples: sugar solution, salt solution, vinegar (acetic acid + water) rubbing alcohol (isopropyl alcohol + water) air (nitrogen, oxygen, carbon dioxide, He, etc)  HETEROGENEOUS MIXTURE - does not have a uniform composition COLLOIDS - characterized by (a) Tyndal effect (scattering of light) (b) brownian movement (zigzag, random motion of particles) Examples: paints, smoke, fog, gel, styrofoam, mayonnaise, gems SUSPENSION – particles are larger than colloids - particles settle down CHANGES IN MATTER PHYSICAL CHANGE - alters the form or state but not the composition of substance CHEMICAL CHANGE - involves change in the structure and composition of substance CHEMICAL CHANGE EXOTHERMIC REACTION - release heat in the surrounding ENDOTHERMIC REACTION - heat is absorbed from the surrounding  LAW OF CONSERVATION OF MASS - States that matter is neither created nor destroyed in a chemical reaction All changes are accompanied by change in energy. LAW OF CONSERVATION OF ENERGY - states that energy cannot be created nor destroyed although energy can assume many different forms that are inter- convertible. Energy – capacity to do work FORMS OF ENERGY  Kinetic energy – energy produced by moving objects by virtue of its velocity  Potential energy – energy available by virtue of its position  Radiant energy – solar energy from the sun  Thermal energy- associated with random motion of atoms and molecules  Chemical energy – stored energy within the structural units of chemical substances\  Nuclear or atomic energy – energy released when atom is split References Brown,B.S, Holme,T.A,(2012) Chemistry for Engineering Students, 2ed: Cengage Learning Asia Pte Ltd Chang, R. (2010). Chemistry. Boston: McGraw-Hill Higher Education. Masterton,W.L, et al (2018) Principles and Reactions: Chemistry for Engineering Students, Cengage Learning Thank you for listening!