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Chapter 2. Dr. C.’s AP Chemistry Lake Dallas High School Fall 2014. Law of Conservation of Mass. Mass is neither created nor destroyed in a chemical reaction (it just changes form) Burning of a candle. Law of Definite Proportion.
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Chapter 2 Dr. C.’s AP Chemistry Lake Dallas High School Fall 2014
Law of Conservation of Mass • Mass is neither created nor destroyed in a chemical reaction (it just changes form) • Burning of a candle
Law of Definite Proportion • A given compound always contains exactly the same proportion of elements by mass • H2O
Dalton’s Atomic Theory • Each element is made up of tiny particles called atoms • The atoms of a given element are identical; the atoms of different elements are different in some fundamental way • Chemical compounds are formed when atoms of different elements combine with each other. • Chemical reactions involve reorganization of the atoms (different bonding) but the atoms are not changed.
Modern Atomic Structure • Nucleus (10-13 cm diameter) • Electrons (avg. distance 10-8 cm from nucleus) • Nucleus contains: • Protons & Neutrons • Nucleus accounts for almost all of the atoms mass.
Number of electrons determines the chemical properties of an atom. • The number of protons determines the identity of the atom
Practice • Ca • Fe • Fe2+ • Br-
Groups/Families have similar chemical properties Atomic Radius increases down the groups
Isotopes • Same number of protons, different number of neutrons. • Dalton’s assumption that all atoms of the same element were identical in all their properties.
Which Carbon isotope is the most common/abundant? 12C 13C 14C Why?
Charges on Transition Metals • PbCl2 • MnO2 • CuCl ** Charges must balance each other **
Naming Ionic CompoundsFrom Formula to Name • Metal + Non-metal OR Metal + Polyatomic • 1st Name the cation. • If the cation is a transition metal its charge must be written in ( )’s. • 2nd Name the anion and change its ending to -ide OR Write full name of the polyatomic anion
Practice • CoBr2 • Al2O3 • CaCl2
Naming Ionic CompoundsFrom Name to Formula • Metal + Non-metal OR Metal + Polyatomic • 1st Write the symbol for the cation and its charge. • 2nd Write the symbol for the anion and its charge • 3rd Circle the charges and “cross” them to balance charges.
Practice • Gallium Bromide • Manganese (IV) Oxide • Lead (II) Chloride • Calcium hydroxide
Homework Wednesday We Will Discuss Naming Covalent Compounds and Naming Acids • Work on your journal article • Read pages 54 – 70 • Start on Homework #2 (page 72- 80) 5, 12, 23, 24, 36, 42, 50, 56, 58, 64, 68, 72, 74, 76, 78, 80, 84, 86, 90, 94, 96, 98, 112, 120