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? 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? grams of quinine (molar mass = 324 g/mol) is combusted and found to produce g CO 2, g H 2 O and g nitrogen. Determine the empirical and molecular formulas. Compound contains C,H,N,O

answers 90 grams C 10 H 12 NO (empirical) C 20 H 24 N 2 O 2 (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 g sample of the rocket fuel hydrazine, N 2 H 4, is burned in a bomb calorimeter which contains 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 q reaction 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 -N 2 O – Ionic compounds with polyatomic ions (including oxyanions) Calcium hypochlorite -Ca(ClO) 2 – Acids (Hydrogen with anion) Carbonous acid- H 2 CO 2

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