Chemistry Homework & Review: Past Materials (PDF)

Homework Review pages 53-61 and 66-70 Questions pages 79-85 #17,18,46 (Look up charge of one e-),62,76,101,132 DO NOW A 25.00g sample of HCN contains 12.96g of N and 11.11g of C. Find the mass of carbon in a sample of HCN with a mass of 45.00g? ...

Homework Review pages 53-61 and 66-70 Questions pages 79-85 #17,18,46 (Look up charge of one e-),62,76,101,132 DO NOW A 25.00g sample of HCN contains 12.96g of N and 11.11g of C. Find the mass of carbon in a sample of HCN with a mass of 45.00g?  Rutherford Model of the atom Fill in the chart Mass (amu) Charge Location proton neutron electron Dr. Marie Curie 1895-Concluded radiation must come from within atom First person to win two noble prizes Only person to win in multiple science fields (chemistry and physics) 1909 Ernest Rutherford A student of Thompson Set up an experiment to help confirm The Plum Pudding Model *No actually tested on AP* Majority of particles had zero deflection Few had major deflections What were the major Conclusions of gold foil experiment? 1. Atoms are mostly empty space 2. Most of the mass contained in positively charged nucleus 3. Protons  James Chadwick Problem: Helium atoms found to contain only 2x charge of H atom yet 4x mass of H atom. Discovered that the Neutron was this source of extra Mass Rutherford Model 1 Rutherford Model 2  Look at the periodic table The Periodic table show elements in isotopic notation Isotopic Notation Mass number Sum of protons and Neutrons Total Ionic Charge Sum of the charges of Protons and Atomic number (Z) Electrons Number of protons Defines the element On you periodic table Other isotopic notation 6 C-12.01 C 12.01 How does carbon-12 differ from carbon-14? Atoms with identical atomic numbers but different mass numbers are called isotopes. Isotopic atoms have the same number of protons, but different number of neutrons. Let's take a look... Think Positive How does Mg+2 differ from Mg? Any atom by definition has a neutral charge. In any Ion compare to the number of protons to the number of electrons? Picture it So if isotopes exist, how did we get the atomic mass for the periodic table? Discuss with your neighbor. A sample of an element in nature consists of a mixture of its naturally occurring isotopes. Mo st c o isot mmon ope Practice! Magnesium has three isotopes, with mass numbers 24, 25, and 26. a) write the complete chemical symbol (subscript and superscript) of each. b) how many neutrons are in an atom of each isotope? Average atomic mass Atomic Mass of an element is a weighted average of all isotopes, resulting in fractional values.  Calculating Atomic Mass Weighted Average To the board for the equation Mr. Scheiber PRACTICE: Naturally occurring carbon is a mixture of two isotopes, 12C (98.89%) and 13C (1.11 %). Individual carbon atoms therefore have a mass of either 12.000 or 13.003354 amu. What is the atomic mass of a carbon sample? Calculate the atomic mass for Ne with this isotopic data: Mass # Mass (amu) % 20 19.992 90.51 21 20.994 0.27 22 21.991 9.22 Mass Specto...what? Here is another example... So how does it look? What is the average atomic mass of element X, based on the mass-spec data bellow What is the average atomic mass of element X, based on the mass-spec data bellow 107.87AMU Practice! 1) Naturally occurring carbon is a mixture of two isotopes, 12 C (98.89%) and 13C (1.11 %). Individual carbon atoms therefore have a mass of either 12.000 or 13.003354 amu. What is the atomic mass of a carbon sample. 2) Calculate the atomic mass for Ne with these isotope: Mass # Mass (amu) % 20 19.992 90.51 21 20.994 0.27 22 21.991 9.22 More Practice Copper has an atomic mass of 63.55amu. It has two naturally occurring isotopes, Cu-63 with a mass of 62.94amu and Cu-65 with a mass of 64.93amu. Calculate the percent abundance of each. Strontium has four stable isotopes, Strontium-84 has a very low natural abundance, but 86Sr, 87Sr and 88Sr are all reasonably abundant. Which of these more abundant isotopes predominates?