Chem 101 1nd EditionExam # 1 Study Guide Lectures: 1 - 6Lecture 1 (August 27)Chapter 1: Basic Concepts of ChemistryA theory is a hypotheses (or a well tested unifying principle that explains a law) which is proven by data. Data can be qualitative informative (something you can observe, has no numbers involved) or quantitative informative (Something you can measure, numerical data). A series ofreproducible experiments (may) result in a law or general rule. There are 3 states of matter (anything that takes space and has mass): 1. Solid- has a rigid shape and a fixed volume. It’s external shape may reflect the atomic and molecular arrangements and its structure is reasonably well understood.2. Liquid- has no fixed shape. They don’t expand to fill a container completely and its structure isn’t well understood.3. Gas- has no fixed shape. They expand to fill a container completely and has a well defined theoretical understanding.In addition to there being 3 states of matter, there are levels of matter. 1. Macroscopic Level- processes and properties on a scale large enough to be observed directly; 100’s of cm 2. Submicroscopic or Particulate Level- representations of chemical phenomena in terms of atoms and molecules; 10^(-12) cmMatter can again be classified into mixtures and Pure substances. 1. Mixtures- have more than one substance present. Mixtures are classified further into 2 subgroups: 1. Homogeneous Mixture- two or more substances in the same phase. It has a uniform composition and its components aren’t visually distinguishable (Salt water) 2. Heterogeneous Mixture/Solutions- has no uniform composition and components are often visually distinguishable. You can separate heterogeneous mixtures with a filter if the mixture is in the liquid phase. (Milk, muddy water, sand and water, chocolate chip cookie) 2. Pure Substances- have a fixed composition and cannot be further purified. Pure Substances are classified further into 2 subgroups: 1. Elements- consist of only one type of atom. There are currently 118 elements which are all recorded in the Periodic Table of Elements. Mercury is the only liquid at room temperature 2. Compounds- can be further reduced into two or more elements. The reaction oftwo elements results in a compound. All compounds consist of molecules (the smallest discrete units that retain the composition and chemical characteristics of the compound) or ions (electrically charged atoms or groups of atoms). Compounds are held together by chemical bonds.Chemical Symbols allows for us to connect observation (what we can see, microscopic level) with imagination (what we cannot see; particulate level). Symbols represent what we understand.Physical Properties are proprieties which can be observed and measured without changing the composition of a substance. Color, state of matter, melting point, density (D+M/V), solubility and viscosity are all examples of physical properties. Physical Properties can be either:1. Extensive Properties- depend on the amount of a substance present. (mass and volume) 2. Intensive Properties- do not depend on the amount of substance (density and melting point)Physical Changes describe changes in physical properties. They indicate whether (and how readily) a material undergoes a chemical change with another material. A chemical change is when one or more substances (the reactants) are transformed into one or more different substances (the products).Lecture 2 (August 29)Matter consists of atoms and molecules in motion. Energy is the capacity to do work and can be classified as kinetic or potential Kinetic energy is energy associated with motion and includes thermal energy (the motion of atoms, molecules or ions at the submicroscopic level. All matter has thermal energy), mechanical energy (the motion of macroscopic objects such as a moving tennis ball or automobile), electrical energy (the movement of electrons in a conductor, and acoustic energy (the compression and expansion of the spaces between molecules in the transmission of sound Potential energy is the energy associated with changed or partially changed particles and includes gravitational energy (energy possessed by a ball held above the floor and by water at the top of a water wheel), chemical energy (energy stored in fuels), electrostatic energy (energy associated with the separation of two electrical charges), and energy stored in an extended spring. The Law of Conservation of Energy states that energy can neither be created nor destroyed. Orthe total energy of the universe is constant.To record and report measurements, the scientific community has chosen a modified version of the metric system. This decimal system, used internationally in science, is called the Systeme International d’Unites (International System of Units) or simply SI. The 7 Basic units are: Measured Property Name of Unit Abbreviation1. Mass Kilogram kg2. Length Meter m3. Time Second s4. Temperature Kelvin K5. Amount of Substance Mole mol6. Electric Current Ampere A7. Luminous Intensity Candela cd*NOTE that Fahrenheit is not an SI unit. Celsius and Kelvin are both commonly used. However Kelvin is more widely used. T(°C) = (T(°F)-32) x (5/9)T(K) = 1K (T °C + 273.15 °C) 1 °C °F °C KBoiling Point 212 100 373.15Freezing Point 32 0 273.15The base units are modified by a series of prefixes which you will need to memorize Prefix Abbreviation MeaningGiga- G 10^(9) (billion)Mega- M 10^(6) (million)Kilo- k 10^(3) (thousand)Deci- d 10^(-1) (tenth)Centi- c 10^(-2) (one hundredth)Milli- m 10^(-3) (one thousandth)Micro- μ 10^(-6) (one millionth)Nano- n 10^(-9) (one billionth)Pico- p 10^(-12)Femto- f 10^(-15)The Common units of length on the molecular scale areNanometers (1nm = 1 x 10^(-9)m) Ångstrom (1Å = 1 x 10^(-12)m)Picometers (1Å = 1 x 10^(-12)m)Dimensional analysis converts one unit to another by using conversion factors. The resulting quantity is equal to the original quantity, it differs only by the units. A good example of why we use this is the base unit of mass in the SI system is the kilogram, but the gram is more commonly used, so we use conversion factors to
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