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UofL CHEM 101 - Exam 1 Study Guide

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Chem 101 1st EditionExam # 1 Study Guide Lectures: 1 - 7Lecture 1 (January 7th)Introduction to Matter Know the definitions for Matter, Particles, Solids, Liquids, Gas, and Atom. Be able to classify matter into pure substance and mixture; classify pure mixture into elements and compounds;Matter: Anything that has mass and occupies space. There are 3 primary states of matter:There are 3 primary states of matter:- Solid: Particles of solids are uniform and closely packed to one another. Their position does not change. Particles of solids move or vibrate to a degree unless the object in question is frozen. Volume and shape are constant. When solids are heated the particles gain energy and the solid becomes a liquid.- Liquid: Particles of liquids are farther apart than those seen in solids but still relatively close to one another. There is no fixed arrangement of particles and they can occupy anylocation in the object as there is more allowance for movement. When you heat a liquid it becomes a gas because you energize and excite the particles. Freeze it and it will deplete particle energy to form a solid. - Gas: Characterized by large gaps between particles that are moving freely at high speeds. Gas can be compressed- unlike solids or liquids because of the space between particles in this state. Particles are in constant motion however they never average a speed. Particles move quickly because they contain energy. Like liquids, gas conforms to the container it is in. Particles: Is a term used to refer to atoms, molecules or ionsAtom: the smallest unit of an element that retains all of the properties of that element.Pure Substances: is any form of matter that has a uniform composition and cannot be separatedby physical methods (i.e. filtration or evaporation). -Elements and Compounds are 2 subclasses of pure substancesCompounds: a substance made up of atoms from 2 or more elements.-There are 2 broad categories of compounds: Molecular and Ionic-Molecules are the simplest units of a molecular compound.-A formula unit is the simplest unit of an ionic compound.-The type of compound a substance is depends on the type of bond present.-Important to keep in mind** the elements that make up either type of compound cannotbe separated by physical methods, but only by a chemical reaction.Lecture 2 (January 12) Mixtures and PropertiesIntroduction to mixtures; be able to classify substances into homologous and heterogeneous mixtures. You are responsible for memorizing the elements of the periodic table with the atomic numbers 1-38, from 49-56, Au and Ag. Recognize which elements are metal, nonmetal, and metalloids. Be able to apply the scientific method for a given exam question. You must be able todistinguish between chemical and physical change, and exemplify chemical and physical properties. Memorize the metric units listed below. Be able to define density, mass, and weight. Be able to do any kind of conversion, given the equality (example: 1in= 2.54cm). You can find practice questions in your book and online. Mixture: is 2 or more pure substances that are physically combined but not chemically bonded together. Mixtures have 2 subclasses:-Homogeneous Mixtures: are mixtures in which the substances that compose it are so evenly distributed that a sample from any part of the mixture will be chemically identical to a sample from any other part.-Heterogeneous Mixtures: is one in which the composition varies from one region of the sample to another.The Periodic Table of Elements: This shows all the known chemical elements. Memorize 1-38, 49-56, Au (79) and Ag (47). Know their atomic symbol, atomic number, and be able to distinguish which are metals, nonmetals, and metalloids:-Atomic Symbols: Letters of ‘symbols’ are used to represent the elements of the periodic table. Most are derived from the elements name (He- Helium). However, some elementssuch as gold (Au) and sodium (Na) are represented by symbols derived from the Latin names of the element.-Atomic Number: is the number of protons in the nucleus of an atom, which determines the chemical properties of an element and its place in the periodic table. This number is normally found in the top right hand corner of each elemental square. -Atomic Mass: the mass of an atom of a chemical element expressed in atomic mass units. It is approximately equivalent to the number of protons and neutrons in the atom (the mass number) or to the average number allowing for the relative abundances of different isotopes. -For example Sodium (Na) has an atomic number of 11, and an atomic mass of 22.990-Metals: Share the following properties: They are good conductors of electricity and heat, they are solid at room temperature, and they generally have very high melting points-Nonmetals: Share the following properties: They are not good conductors, they can be found as liquids, solids or gases depending on the element and they generally have lower melting points than metals-Metalloids: Have properties between the two extremes shown by metals and nonmetals. There isn’t a sharp line that distinguishes a metalloid from a metal or nonmetal. Rather, the changes are gradual in the physical properties of the elements.-Examples of Metalloid elements: B, Si, Ge, As, Sb, Te, Po, and At-Noble Gases: any of the gaseous elements helium, neon, argon, krypton, xenon, and radon, occupying Group (18) of the periodic table. They were long believed to be totally unreactive but compounds of xenon, krypton, and radon are now known. They do not react easily. The Scientific Method is a systematic method for problem solving and the steps are as follows:1. Determine the nature of the problem.2. Collect and analyze all relevant data.3. Form an educated guess, called a hypothesis, as to what the answer to the problem faced is. 4. Test your hypothesis.5. If your hypothesis holds up to testing, you are finished. If not, go back to step two. Fora hypothesis to hold up to testing the test would have to be replicable.Chemical Change: When matter undergoes a chemical reaction and forms a new substance we call this a chemical change. -Chemical properties: are used to describe the potential chemical reactions a substance can undergo. Some examples of this include flammability (the potential to react rapidly with O and burst into flames, producing light and heat), rusting (the ability of a substance to react with O, forming rust) and explosiveness (the tendency of compounds such as nitroglycerin


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