09 01 15 09 08 15 Chemistry 101 Chapter 1 What is chemistry Definition study of matter and changes it undergoes using energy Is a central science Physics chemistry in motion Bio chemistry in a cell Engineering application of sciences Why is it hard Terminology Words numbers equations Skeptic looks at all sides and chooses the best Organic contains carbon and hydrogen All chemists eat drive a car cook Chemical intuition Biggest challenge getting standard units terms and numbers Chemistry and its method Parts of Scientific Method Observation Hypothesis Data Collection Summary of data Record what you do proof Laws and theories Hypothesis Laws and Theories Hypothesis tentative explanation or prediction w knowledge Requires both qualitative and quantitative in experiments Quantitative numerical data Supports claims Ex mass temp Qualitative non numerical observations Ex color physical appearance relation that is the same in all conditions Narrow statement the laws based on them Binds observations data together Law a concise verbal or mathematical statement of a behavior or a Theory well tested unifying principle that explains a body of facts and 1 09 01 15 09 08 15 Capable of suggesting new hypotheses Based on carefully determined and reproducible evidence Can change w new facts Umbrella statement Systematic Approach Scientific method Observation representation interpretation observation repeating cycles Goals of Science What makes a good scientist Patience Knowledge Hard work Luck Goals Prediction and control Can be dangerous Understanding and Explaining Examples Dilemmas and integrity in science Results can be inconclusive Guidelines 4 rules Results should be reproducible Research should be reviewed detailed Conclusions should be reasonable and unbiased Credits should be given where it is due Sustainability and Green Chemistry Began to take root 20 years ago New ways of doing things w lower pollution levels Matter Classifying matter Anything that occupies space and has mass Governed by 2 things compositions and energy States of Matter and Kinetic Molecular Theory State gas liquid solid At low temps all matter is solid As temp increases liquids becomes gases Kinetic Molecular Theory of Matter All matter consists of small particles Solid packed closely regular in array vibrate in avg positions Liquid random arrangement fluid not confined to position Gas parts are far part moves around volume container fluid There are net forces between particles in all states 2 Gas small Solid liquid large Determines properties of matter 09 01 15 09 08 15 Higher temp faster movement Energy of motion kinetic acts to overcome the forces of attraction Energy causes change in state between parts Matter at the Macroscopic and Particulate Levels Macroscopic world of experiments and observations observed by the naked Submicroscopic particulate only seen by microscope atoms and molecules eye Matte r Mixtures Substance s Homogenous Heterogeneo us Pure Substances Solutions mixture of liquid water and dissolved substances Has unique properties which it can be recognized Melting boiling point Cannot be separated into 2 species by any physical means Physical means used to separate a mixture into its pure components Ex distillation using a magnet Mixtures Heterogeneous and homogenous Mixture 2 or more pure substances that can be separated by physical techniques Retains specific identities Heterogeneous uneven texture not uniform throughout Homogenous 2 substances in same phase Ex cement Ex milk soda solder Often called solutions 3 MatterMixturesHomogenousHeterogeneousSubstances 09 01 15 09 08 15 Elements only 1 type of atom cannot be separated by chemical means Uniform throughout 118 elements Ex Au Al Pb O C S 82 occur naturally 36 elements created by scientists chemical properties chemical bonds at fixed proportions Referred as chemical compounds Can be changed by chemical means Atom smallest particle of an element that retains the characteristics Compounds pure substances composed of 2 elements held together by Molecules smallest discrete unit that retain the composition and Chemical Formula represents compound Ions electrically charged atoms or groups of atoms chemical characteristics Ex H2O 2 Hydrogen atoms w 1 Oxygen Physical Properties properties that can be observed and measured w o Chemical Properties indicates whether and sometimes how readily a changing the composition of a substance Ex height weight color conductivity Density ratio of mass to volume Temperature affects the numerical values of its properties material undergoes a chemical change w another material Ex combustion fire food digestion Ex Questions Physical Chemical Sugar dissolving in water Methane burning in air Extensive and Intensive Properties Extensive depends on amount of substance present size dependent Ex mass and volume energy length Intensive do NOT depend on amount Ex density temp color Useful in identifying material Physical and Chemical Changes Physical changes changes in physical properties Identity of substance is sustained No new chemicals Ex melting dissolving or more other substances products Alter composition reaction 4 Chemical changes 1 or more substances reactants are transformed into 1 Chemical equation representation of chemical reaction 09 01 15 09 08 15 Left reactants Right products Ex hydrogen burns air to form water Energy Some basic principles Defined as the capacity to do work Kinetic energy motion Potential energy results from an object s position or state and included Types of energy height springs and chemical bonds Ex chemical position Radiant comes from the sun primary source Thermal associated w motion of atoms molecules Chemical stored w in bonds of chemical substances Nuclear stored w in collection of neurons and protons in the atom Conserved most of the time Ex chemical kinetic Law of Conservation of Energy Correct title First Law of Thermodynamics Thermodynamics movement of energy Defined as energy can neither be created nor destroyed Total energy of the universe is constant Can be converted Critical Parts number and unit SI units created by the General Conference of Weights and measurements 2 major parts base unit and prefix Math Review Measurements quantitative Measurements and importance Length ruler m Mass balance g kg Volume beaker flask bottle mL L Temperature thermometer oF oC K standard units Base unit tells us what it is Prefix tells us size of it Mass measure of what is there Mass vs Weight SI
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