Chemical Reactions Types of Reactions
Reactions and Energy Exothermic – energy releasing rxns Explosion, burning of fuel and rusting of iron Endothermic – energy absorbing rxns Cooking of food, electrolysis Changes of state – adding or releasing energy is common
Reactions and Energy Law of Conservation of Energy Energy can be converted from one form to another but the total quantity of energy is constant Remember Bond Energy to help this theory make sense
Types of Reactions Four main types of reactions 1. Synthesis 2. Decomposition 3. Single Displacement 4. Double Displacement Synthesis One or more reactants combine to produce a new product X + Y XY
Types of Reactions Decomposition A compound breaks down into two or more simpler compounds or elements. XY X + Y
Types of Reactions Single Displacement One element takes the place (displaces) another element or compound. A + BX AX + B or AX + Y AY + X 2Na (s) + 2H 2 O (l) 2NaOH (aq) + H 2 (g) + thermal E
Types of Reactions Double Displacement The cations of two different compounds exchange places, forming two new compounds WX + YZ WZ + YX A precipitate or water will be formed as products
Reactions Involving Carbon Organic Chemistry Organic Chemistry Also all compounds containing carbon are organic (except CO 2, CO and ionic carbonates) Also all compounds containing carbon are organic (except CO 2, CO and ionic carbonates) Hydrocarbon Hydrocarbon Used as fuels as reactions are exothermic Used as fuels as reactions are exothermic Crude oil and natural gas Crude oil and natural gas When burned in a plentiful supply of oxygen it is known as complete combustion When burned in a plentiful supply of oxygen it is known as complete combustion Hydrocarbon + oxygen carbon dioxide + water Incomplete combustion = poor supply of oxygen Incomplete combustion = poor supply of oxygen Still exothermic, but not as much heat given off Still exothermic, but not as much heat given off Carbon (soot) and carbon monoxide also given off Carbon (soot) and carbon monoxide also given off