Chem 102 Exam I Study Guide PART I NNNN oooo tttt eeee bbbb oooo oooo kkkk CHEM 102 CCCCrrrreeee aaaatttt eeee dddd TTTT aaaagggg ssss 9 23 2012 10 26 AM CHEM 102 Study Guide Pre Lecture 8 27 12 UUUU pppp dddd aaaatttt eeee dddd 9 23 2012 3 09 PM 2 2 Fundamental Chemical Laws Antoine Lavoisier verified the Law of Conservation of Mass mass is neither created nor destroyed in a chemical reaction quantitative experiments combustion involves Oxygen he named Oxygen life is supported by Oxygen similar to combustion 1st Modern Chemical Textbook Elementary Treatise on Chemistry Joseph Proust Law of Definite Proportions A given compound always contains exactly the same proportions of elements by mass DALTON Law of Multiple Proportions ex 2 1 Jamieson s Lecture Notes 2 3 Dalton s Atomic Theory 1808 1 Each element is made up of atoms 2 Atoms of the same element identical Atoms of different elements different in fundamental ways 3 When atoms of different elements combine together COMPOUND a given compound always has the same relative s and types of atoms 4 Atoms themselves are not changed in a chemical reaction they are changed in the way they are brought together 7 diatomic elements Hydrogen Nitrogen Oxygen Fluorine Chlorine Bromine Iodine 2 4 Early Experiments to Characterize the Atom J J Thomson CATHODE RAY TUBES 1898 1903 ray was negative and repelled by the negative pole of an applied electric field ELECTRON he thought the ray was a stream of negative charged particiles He figured out 1 electrons were made of electrodes from all types of metals ALL ATOMS HAD ELECTRONS 2 Atoms are neutral so they must have had positive particles canceling out the negative electrons this led to the PLUM PUDDING MODEL Radioactivity Radioactive Decay the spontaneous decomposition of a nucleus to form a different nucleus gamma rays high energy light beta particles high speed electron alpha particles 2 charge twice the electron and with the opposite sign Ernest Rutherford s 1911 Experiment pg 49 NUCLEAR ATOM alpha particles protons repelled from the center of the atom positively charged nucleus 2 5 The Modern View of Atomic Structure An Introduction If all atoms are composed of these same components why do different atoms have different chemical properties THE AND ARRANGEMENT OF THE ELECTRONS Isotopes atoms with the same number of protons but different NEUTRONS insert drawing here of element symbol and mass and atomic numbers Because an atom s chemistry is from its electrons isotopes show almost identical chemical properties R electrons intermingle to form molecules and bonds Covalent electron sharing Ionic completely giving or receiving electrons 2 6 Molecules and Ions Chemical Bonds the forces that hold atoms together in compounds 1 Covalent Bonds sharing electrons molecules 1 Chemical Formula CO2 2 Structural Formula insert drawing here of structural formula of Co2 Models 1 Space Filling Model 2 Ball and Stick Model 2 Ion a group of atoms that has a net positive or net negative charge ex Sodium Chloride 1 Cation 2 Anion negative Ionic Bonding the force of attraction between oppositely charged ions Ionic Solid a solid consisting of oppositely charged ions Polyatomic ions many Discussion 1 8 28 12 Significant Figures Rules 1 Anything but zero sig fig 304 3 sig figs 0 1 1 400 1 4 00 x 10 2 3 Anything that follows a period counts as a sig fig 2 Start counting sig figs at a non zero number 0 003840 4 leading zeros don t count 3 If nonzero everything in between even zeros count 6 07 x 10 15 3 Lecture 1 8 29 2012 ATOM History Ancients 1000 BC Ores make metal weapons and ornaments Egyptians embalming the dead used chemistry but didn t understand chemistry Greeks 400 BC 1st time using the scientific method inquiry atmos atom all matter is made up of 4 elements fire earth air water infinitely divisible or indivisible everything in particles or an end all unbroken particle 2000 years later ALCHEMY majority were frauds fakes Goal turn all metals into GOLD metallurgy Bauer Father of Metallurgy extraction of ores into metals even though metals weren t considered to be real elements Paracelsus Swede 1st medicinal application of minerals birth of chemistry in medicine 17th Century Robert Boyle 1627 1691 QUANTITATIVE MEASUREMENTS states that its the only true science all experiments are measurable Element all matter that could not be divided Boyle s Gas Law pressure is inversely proportional to volume p 1 volume but he still thinks that metal can be turned into Gold metal still not an element 18th 19th Century Lavossier French Law of Conservation of Matter mass is neither created nor destroyed in a chemical reaction Joseph Proust Law of Definite Proportions a single compound contains the same proportions of atoms John Dalton True Father of the Atom All compounds have the same number of atoms C s O2 g CO CO2 QUANTITATIVE Getting closer to chemistry Law of Multiple Proportions Multiple proportions in the ratio of C and O2 multiple compounds with different proportions element made of tiny particles called atoms all atoms of the same element are equal compound a combination of 2 or more atoms CHEMISTRY IS A REORGANIZATION OF ATOMS FIRST TRUE DEF OF CHEMISTRY Avogadro Pv nRT ideal Gas Law n at the same temperature and pressure all gases have the same number of particles J J Thomson Cathode Ray tube experiments determined that small negatively charged particles existed electron atom consists of positive and negative particles plum pudding model Ernst Rutherford 1911 insert drawing here birth of the nucleus and makings of the modern atom Masses proton 1 67 x 10 27 kg charge of 1 neutron 1 67 x 10 27 kg charge of 0 electron 9 1 x 10 31 kg charge of 1 Nucleus contains positive protons and neutral neutrons Nucleii of 2 atoms NEVER interact electrons are the sole particles that behave in chemical reactions properties and chemistry protons atoms identity electrons atoms behavior Pre Lecture Notes 9 3 94 7 1 Electromagnetic Radiation Electromagnetic Radiation radiant energy that exhibits wave like behavior and travels through space at the speed of light in a vacuum Waves 1 Wave Length LAMBDA the distance between 2 consecutive peaks or troughs in a wave 2 Frequency NU the number of waves cycles per second that pass a given point in space LAMBDA NU c wavelength in meters frequency in cycles second speed of light 3 Speed C speed of light 2 9979 x 10 8 m s 1 s or s 1 hertz Radiation energy transfer 7 2 The Nature of Matter Planck Planck