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AP Final Review. Nuclear Chemistry . Main topics: Types of decay Alpha Beta Positron Basic Half life problems . Example problems. What type of decay results in a U-238 nucleus becoming a Th-234 nucleus? What type of decay results in the atomic number decreasing by 1?
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Nuclear Chemistry • Main topics: • Types of decay • Alpha • Beta • Positron • Basic Half life problems
Example problems • What type of decay results in a U-238 nucleus becoming a Th-234 nucleus? • What type of decay results in the atomic number decreasing by 1? • What is the half life of a substance if an initial amount of 30 grams of the substance has a mass of only 3.75 grams after 60 years.
Types of Reactions • Decomposition- (redox) • Synthesis- (redox) • Double Replacement (neutralization or ppt) • Single Replacement (redox) • Combustion – organic compound + oxygen carbon dioxide and water
Combustion example problem • What mass of carbon dioxide is produced if 30 grams of propane are combusted? • 0.487 grams of quinine (molar mass = 324 g/mol) is combusted and found to produce 1.321 g CO2, 0.325 g H2O and 0.0421 g nitrogen. Determine the empirical and molecular formulas. Compound contains C,H,N,O
answers • 90 grams • C10H12NO (empirical) C20H24N2O2 (molecular)
Calorimetry • q=msΔT • Remember units! q=J m=g s= J/gK T=⁰C or K • Bomb calorimetry- the bomb has a heat capacity where the mass has already been factored in, so we don’t need the mass in the formula any more. • Just use q= heat capacity * ΔT
Example Problem • When a 10.00 g sample of the rocket fuel hydrazine, N2H4, is burned in a bomb calorimeter which contains 1200. g of water, the temperature rises from 24.62°C to 28.16°C. If the C for the bomb is 840. J/°C, calculate • qreaction for combustion of a one-gram sample • Molar heat of combustion for hydrazine
answers • 297 J • 9530 J/mol
Limiting Reactants • Whenever you are asked for an amount of product produced ALWAYS think Limiting reactants!
Example problem • At STP, 3.0 liters of hydrogen gas react with 2.0 liters of nitrogen gas to form ammonia. If the reaction goes to completion, how many grams of ammonia will be formed?
answers • 1.5 grams
Naming • Types: • Binary Ionic compounds (only 2 element) • Sodium chloride -NaCl • Molecular compounds (covalently bonded) • Dinitrogen monoxide -N2O • Ionic compounds with polyatomic ions (including oxyanions) • Calcium hypochlorite -Ca(ClO)2 • Acids (Hydrogen with anion) • Carbonous acid- H2CO2
Organic Naming • Alkanes- all single bonds (-ane ending) • Methane, ethane, propane, butane, pentane, hexane, heptane, octane, nonane, decane • Alcohols, have OH on the end • Methanol, ethanol, etc.
Naming Practice • Propanol • Potassium acetate • Perchloric acid • Aluminum nitrate • Phosphoric acid • Phosphorus pentachloride • Butane • Bromic acid