Popular in General Chemistry Lecture I
CHE 106 - M001
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This 4 page Class Notes was uploaded by Hayley Kong on Thursday September 10, 2015. The Class Notes belongs to CHE 106 - M001 at Syracuse University taught by R. Doyle in Fall 2015. Since its upload, it has received 54 views. For similar materials see General Chemistry Lecture I in Chemistry at Syracuse University.
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Date Created: 09/10/15
Chapter 1 Introduction Matter and Measurement 11 o Atoms and Molecules o Matter is the material that makes up all things if something has mass and volume it s made of matter 0 Properties are characteristics of different types of matter and allow us to identify what is what 0 Elements are the components that make up all things elements are the components of matter 0 Atoms are typically referred to as the building blocks of matter they are the smallest unit generally that make up elements 0 Molecules are two or more atoms combined in specific ways I Different molecules have different combinations of elements and different structures 0 This allows us to tell them apart 12 0 Classification of Matter 0 States of Matter I Matter can eXist in three different states gas liquid or solid 0 Gas gas does not have a set volume or shape and conforms to its container 0 Liquid liquid also does not have a set shape but does have a certain volume 0 Solid solid has both a set volume and shape relatively I Unlike gases neither solids nor liquids can be compressed into smaller volumes I In gases the molecules move around freely and rapidly hitting each other and the edges of its container I In liquids the molecules move quickly but not as fast as gases and the molecules are closer together than in a gas I In solids the molecules move very little with xed positions and they are packed closely together 0 Pure Materials I A Pure Substance is matter that has set characteristics that are standard and true for every sample 0 EX Water aluminum foil I Elements are the simplest materials can be and cannot be broken down into anything simpler 0 Elements are only one kind of atom I Compounds are two or more elements combined and therefore contain two or more types of atoms 0 Ex Water is a compound composed of the elements Hydrogen and Oxygen I Mixtures are made up of two or more elements that remain those same elements they don t undergo chemical reactions to form new substances it retains its chemical identity 0 Elements I To date 118 elements have been identi ed and vary greatly in characteristics across the periodic table 0 Compounds I The Law of Constant Composition also known as the Law of De nite Proportions was discovered by Joseph Prouse around 1800 and states that the elemental composition of a compound remains constant 0 Mixtures I Most matter is a mixture I Mixtures can be heterogenous or homogenous I Heterogeneous mixtures are mixtures that do not have the same make up characteristics and appearance throughout uniformly I Homogeneous mixtures in contrast are constant throughout the entire mixture 0 Homogeneous mixtures are also known as solutions 13 0 Properties of Matter 0 There are two types of properties of matter chemical and physical 0 Physical properties are characteristics that exist without changing the identity of the composition substance I Ex Boiling point density color etc 0 Chemical properties are related to the substance s makeup during a change or reaction I Ex Flammability 0 Intensive properties are independent of the amount of substance present I Ex Density 0 Extensive properties dependent of the amount of substance present I Ex Mass 0 Physical and Chemical Changes 0 A Physical Change is a change that does not alter a substance s composition rather its appearance I Ex Changing from liquid to gas or all changes of state O A Chemical Change or chemical reaction does alter the composition I Ex Metal rusting 0 Separation of Mixtures O Mixtures can be separated in a variety of ways I Filtration is one way to separate two substances from each other 0 Simply lter out one and then the other is remaining I Distillation is another way the process depends on what the substances are and how well they translate to gases 14 Units of Measurement 0 The standardized units of measurement are those in the metric system 0 These units are called SI Units a french term for international system of units 0 SI units contain pre xes that determine decimal fractions or other units I Ex Centi 10392 0 Length and Mass 0 Length is measured in meters 0 Mass the measurement of how much material is in an object units in kilograms kg 0 Temperature 0 A physical property that tells which way heat is owing heat always ows spontaneously from hotter material to cooler 0 Temperature is measured in Kelvin standardly and commonly on the celsius scale In celsius water boils at 100 degrees and freezes at 0 degrees I In Kelvin the SI unit for temperature 0 Kelvin is absolute zero I K C 27315 I 0C 59 0F 32 or F 95 0C 32 0 Volume 0 Measured in cm3 or length3 0 SI unit of length m cubed is a cube with 1 m length on each side 0 Cubic centimeters can also be written as cc 0 For liquids measured in liters L or milliliters mL 0 Density 0 Density is the amount of mass in a material 0 d mv mass over volume 0 Units gcm3 or gmL 15 Uncertainty in Measurement 0 Exact vs inexact numbers 0 Most exact numbers have de ned values 0 Numbers gathered by measurement are always inexact 0 Precision and Accuracy 0 Precision is a measurement of how closely collected data agrees with each other I How close each point is to one another 0 Accuracy is how close individual measurements are to the desired target 0 Standard deviation is the distance each data point is from the mean 0 Signi cant Digits O O 16 Zeros between nonzero digits are always signi cant Zeros preceding a number are never signi cant I EX 001 has 1 signi cant gure Zeros at the end of numbers are signi cant if the number has a decimal point I EX 00200 has 3 sig gs I EX 30 has 2 sig gs When in doubt about zeros coming after numbers without a decimal point eX 3000 convert the number into scienti c notation I 30 X 103 has 2 signi cant gs When Calculating I When adding or subtracting the nal answer should have the same number of decimal places as the measurement with the least decimal points I When multiplying or dividing the nal answer should have the same number of sig gs as the measurement with the least sig gs Dimensional Analysis 0 Dimensional Analysis is used to convert numbers from one unit to another 0 EX converting a number from ms to mph To convert these numbers one must use a conversion factor such as 60smin O The conversions are set up as fractions so that the units cancel out and the unit you re left with is the one you desire 0 Ex when converting from ms to mph the meters and the seconds units cancel out and only miles and hours remain O Conversions to Volume 0 When converting into volume one can use density as a way to convert from mass to volume or vice versa