Dr St phanie Le Clair Email sleclair psu edu Office Hours Mondays 4 5PM and Fridays 4 5PM Office 103 Whitmore OR e mail me to schedule an appointment and provide 3 time slots that work for you Use your psu email address when emailing me and put Chem 110 in the subject Have your clickers and materials out before class starts 1 Classification of matter Matter Yes Can it be separated by physical means No Pure substances Mixtures Yes Is the composition uniform Homogeneous mixtures No Heterogeneous mixtures Yes Can it be decomposed by chemical means Compounds Separation by physical means Pure substances No Elements Chemical combination of two or more elements Physical means use the substances differing physical properties e g density solubility melting point etc 2 Chemical means use a reaction e g combustion reaction with acid etc Pure substances F01 3 5 found in Lesson 01 3 3 4 What is an atom composed of Subatomic particles Experiments found that both charged and neutral particles make up the atom The particles found in the atom are called subatomic particles The following three subatomic particles affect chemical properties Symbol Mass amu Proton p 1 1 Electron e 0 0005 1 Neutron n 1 Charge au 0 where 1 amu 1 atomic mass unit 1 66054 x 10 24 g or 1 g 6 022114 x 1023 amu We define the mass of 12C as exactly 12 amu so 1 amu 1 12 mass of carbon 5 How many subatomic particles atomic mass 12 6 C Atomic symbol atomic Nucleons particles found in the nucleus protons and neutrons Atomic number tell the identity of element the of p in the nucleus Mass number mass p n total of p n total of nucleons 6 What is the structure of the atom An atom is almost entirely empty space F01 1 1 Atom Diameter 0 1 0 5 nm 10 14 m Nuclear diameter 10 5 nm 10 10 m Atom diameter 10 000 x nuclear diameter 1 nm 10 9 m 10 1 nm angstrom 7 Putting it into perspective The size of the nucleus relative to the atom Let s say the nucleus has a diameter the size of a mechanical pencil eraser 6 mm How big would the diameter be for entire atom 6 mm x 10 000 60 000 mm x 1m 60 m diameter 1000 mm 8 Ions versus neutral atoms Atoms can lose or gain electrons to become more stable more on this later For neutral atoms of protons of electrons For ions of protons of electrons excess negative Anions have a net charge of electrons positive deficiency Cations have a net charge of electrons Formation of anion Formation of cation F01 3 1 9 Clicker question clicker frequency AD How many protons electrons and neutrons does a 57Fe3 ion have A 57 neutrons 26 protons and 23 electrons B 31 neutrons 57 protons and 57 electrons C 31 neutrons 26 protons and 26 electrons D 31 neutrons 26 protons and 23 electrons E 57 neutrons 26 protons and 26 electrons 10 Clicker question Which of the following statements is are true regarding the number of protons in an atom I It gives you the element s atomic number II It gives you the number of electrons in a neutral atom III It gives you the identity of the element IV It changes based on the charge of the atom A I and II B I and III C II and III D I II and III E I III and IV 11 Isotopes Isotopes are atoms that have the Same of same atomic number but different mass number proton same element Different of neutron different number of mass For example there are three naturally occurring isotopes of uranium 234U 235U and 238U 235U is used for nuclear bombs and reactors The atomic mass weight given on the periodic table is the weighted average of atomic masses of naturally occuring isotopes 12 Isotope abundance and atomic weight Avg atomic weight fractional natural abundance isotope mass The atomic weight and isotope mass are in units of amu mass number If you are not given the exact isotope mass in a problem use the The natural abundance of isotopes can be given as a percent abundance or a fractional abundance The fractional natural abundance is the isotope abundance 0 1 0 83 This is just the percent abundance as a decimal Example 83 is the sum of fractional abundances 1 Not on data sheet 13 Example calculation Carbon has two isotopes 12C 98 93 and 13C 1 07 The mass of 13C is 13 00335 amu What is the average atomic weight of carbon Avg atomic weight fractional natural abundance isotope mass Avg atomic weight for C 0 9893 12 amu 0 0107 13 amu 12 011 amu 14 Your turn Clicker question The natural abundance of 79Br is 54 8 What is the atomic weight of the only other isotope of Br A 77 amu B 78 amu C 80 amu D 81 amu E 82 amu 15 Lesson 01 2 Avogadro s number 16 What is this mystical thing called a mole Unfortunately we cannot see atoms or molecules or weigh individual atoms or molecules Instead we can measure moles of atoms and molecules Definition 1 mole is defined as the number of atoms in exactly 12 g of 12C NA 6 02214 x 10 23 amu Avogadro s number 1 mole of something 6 02214 x 10 23 of something Is that a lot Bill Gates has a net worth of 76 000 000 000 Avogadro s number is 602 200 000 000 000 000 000 000 https kidjeice files wordpress com 2014 06 wpid screenshot 2014 06 25 06 44 21 png w 705 17 MOLE Connection between microscopic what we don t see atoms and macroscopic what we see Saying a mole is just like saying a dozen It is just a way to count atoms molecules etc You can have one mole of anything 1 mole of atoms 6 02214 x 10 23 atoms 1 mole of molecules 6 02214 x 10 23 molecules 1 mole of particles 6 02214 x 10 23 particles MW 18 amu 18 g 1 mole H2O 6 022 x 1023 molecules of H2O 18 What could we do with a mole of Hershey bars Given that one Hershey bar is 0 1365 meters long The Andromeda II galaxy is 2 13 million light years away from the Earth This corresponds to 2 02 x 1022 meters With a mole of Hershey bars 6 022 x 1023 Hershey bars we would be able to cover a distance of meters 0 1365 Hershey bar x 6 022 x 1023 Hershey bars 8 220 x 1022 meters This means we could build a bridge between Earth and the Andromeda II galaxy that would be four Hershey bars wide And we would still have 1 4 x 1021 meters of Hershey bars left over so the fifth layer could only span 7 of the way http www kolumbus fi dirty Album SW80ED m31 2 jpg not drawn …