INTRODUCTION TO CHEMISTRY 101 o Chemistry o Hypothesis o Theory identification of a substance of which matter is composed the ways in a well tested unifying principle that explains a body of facts and the laws a tentative explanation or prediction based on experimental which they interact combine and change and the use of these properties to form new substances observations based on them It is capable of suggesting new hypotheses that can be tested experimentally Law seems always to be the same under the same conditions color smell appearance no numbers mass volume time density numbers will have units A concise verbal or mathematical statement of behavior or a relation that o Qualitative o Quantitative o Scientific Integrity and Reporting o Results should be reproducible o Results should be reported in the scientific literature in detail for others to use or reproduce o Conclusions should be reasonable and unbiased o Credit should be given where it is due Chapter 1 Classification of Matter Physical state o Solid definite shape and volume with least amount of KE o o Gas indefinite shape and volume with most amount of KE Liquid indefinite shape definite volume moderate KE Composition o Element o Compound o Mixture Heterogeneous components easily distinguishable Homogenous two or more substances of the same phase not easily distinguishable When separated components of both mixtures yield pure substances Boiling Point Distillation State of Matter Filtration Intermolecular Forces Chromatography Vapor Pressure Evaporation Density Decantation Magnetism Magnets Solubility Filtration o Pure substances Compounds anything that can be turned into more elements may not have the same characteristics Ex Water does not have the same characteristics as oxygen and hydrogen Cannot be separated by physical means Chemical compounds Molecules molecular formula H2O or ionic formula units Elements consist of only one type of atom and cannot be further simplified Ex Hydrogen and oxygen cannot be broken down any further Atom the smallest unit of an element that has all of the properties of an element Molecule The smallest unit of a pure substance that has all of the properties of that substance It may contain more than one atom and more than one element Ex C6H12O6 is one glucose molecule o o Intermolecular forces interaction between two or more molecules Intramolecular forces interaction within one molecule Physical properties compound o Color state melting boiling points density all contribute to identifying a Intensive do not depend on the amount of substance Ex density o Extensive depend on the amount of substance Ex mass o o Physical properties are a function of intermolecular forces o Can be affected by temperature Ex density of water is seen to change with temperature Ice is less dense than liquid water Water is most dense at about 4 C Physical Changes o Sublimating changing from a solid to a gas o Evaporating changing from liquid to gas o Melting changing from solid to liquid o Chromatography physical way to separate a mixture Chemical Changes o A chemical reaction occurs and a change in the composition of a material o Explains how one substance acts in the presence of another o Ex burning or combustion o Electrolysis running electricity through water to change it into hydrogen and oxygen Energy Matter consists of atoms and molecules in motion o Kinetic associated with motion at the particulate level thermal energy state and macroscopic objects throwing a ball Electrical energy movement of electrons in a conductor Sound energy transverse water and compression acoustic o Potential position of objects Gravitational height waterfalls Chemical energy stored in food molecules Nuclear fission and fusion Stored in an extended spring Electrostatic energy associated with charge or partially charged particles CHAPTER 2 ATOMS MOLECULES AND IONS Ions no longer neutral because it gained or lost electrons Nucleus contains the protons and neutrons while the electrons are in an electron cloud surrounding the atom Number of protons number of electrons atomic number Electrons take up space in orbitals Atomic mass u Atomic number number of neutrons The standard today is Carbon 12 6 protons 6 neutrons 12 u Cannot measure the mass of electrons because they re so small Isotopes have the same number of protons but a different number of neutrons that make up the atomic mass Protons and neutrons together nucleons Atomic weight atomic mass Liquid solid more dense water is the exception Percent Abundance 10000 B atoms 1991 10B atoms 10 0129u 8009 11B atoms 11 0093u o o 1991 10000 x100 19 91 10B 8009 10000 x100 80 09 11B 19 91 100 x10 0129u 80 09 100 x11 0093u 1 994 8 817 10 811 Atomic weight Periodic Table Family Names 1A Alkaline metals 2A Alkaline Earth metals 1B 10B Transition metals Copper Silver Gold 3A Boron metals 4A Carbon metals 5A Nitrogen metals 6A Oxygen metals 7A Halogen metals 8A Noble Gases o o o o o o o o o o Structural formula shows the connections bonds Molecular formula shows the number and type of atoms C2H6O Condensed formula indicates how atoms are grouped together CH2CH2OH Molecular formula gives the 3D perspective Ionic compounds made of metals and nonmetals and referred to as salts composed of ions NaCl Ions are charged particles o Cation positive charged loses electrons o Anion negative charge gained electrons Transition elements Cu Cu Copper l ion Cu Cu2 Copper ll ion Nonmetal ion names o H hydride o O2 oxide Polyatomic atoms a special class of ions where a group of atoms tend to stay together Ionic compounds are neutral amount of negative charge equals the amount of positive charge Electrostatic forces attract the cation and anion to each other Coulomb s Law governs the forces o Force k n e n e d2 o The force depends directly on the charges on the ions and inversely on the distance between them Avogadro s number 6 0221415x1023 atoms 1 mole 1 mole x 1 U 1 gram o Molecular mass mass of 1 molecule in amu o Molar mass 1 mole in grams Percentage Composition o atoms of an element atomic weight x 100 formula weight of compound Empirical formulas show only the simplest ration of atoms in the formula Molecular formula show the actual composition of a molecule Hydrates o After heating any mass that remains is due to the salt left o Any mass loss in heating is due to the water loss CHAPTER 3 CHEMICAL REACTIONS Reactants on the left products on the right The numbers in the front are called stoichiometric
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