Chemistry

Claire Rafson Chapter 3 notes 3.1 You can count things by weight 3.2 Atomic mass determined on a mass spectrometer Average atomic mass = atomic mass for the element 3.3 Avogadro?s number = 6.02214 X 10^23 1 mole = avogadro?s number 3.4 molar mass= mass in grams of one mole of the compound 3.5 Percent comp of compounds Mass percent- weight percent can be computed by comparing the mass of carbon Find moles of all divide by smallest number find whole number etc. 3.6 Molecular formula= (empirical formula)n N is an integer To find molec formula take molar mass/ empirical formula mass and that is n SEE PAGE 96 IF CONFUSED 3.7- Chemical Reactions- Reactants on left and products on the right. Aq- dissolved in water 3.8- Balance reactions 3.9- Stoichiometry-

Chapter 2.1- 2.3 (pages 41-48) Law of conservation of mass- Mass is neither created nor destroyed Law of definite proportion- a given compound always contains exactly the same proportion of elements by mass. Law of multiple proportions- When two elements form a series of compounds, the ratios of the masses of the second element that combine with 1 gram of the first element can always be reduced to small whole numbers Dalton?s Atomic Theory- -Each element is made up of atoms -The atoms of a given element are identical -Chemical compounds are formed when atoms of diff elements combine with each other -Chemical reactions involve reorganization of the atoms Dalton prepared first table of atomic masses