Reactions By Mr. M
Reactions Interactions between atoms that create a compound not originally present A reaction is indicated by an arrow Ý means reaction goes both directions ← means reaction goes to the left in the equation ↓ means reaction goes to the right in the equation Next to an element/compound you may see certain symbols (g) means gas (l) means liquid (s) means solid (ppt) means precipitate or an item that appears (aq) means aqueous or dissolved in water
Parts of an equation The equation for a reaction has 2 parts The reactants are what get used up The products are what are formed Reactants ↓ products You can speed up a reaction by adding a catalyst You can slow down a reaction by adding an inhibitor
Types There are several types of reactions (abbreviated rxns) For right now you are only responsible for five types of reactions Combustion Synthesis Decomposition Single displacement Double displacement
Combustion Combustion is also known as burning Carbon compound + O2 ↓ CO2 + H2O It can also be carbon compound +O2 ↓ CO + H2O but this is called incomplete combustion
Synthesis Multiple items make one item only Also called combination or addition or composition General Equation A + B AB Mg + O2 ↓ MgO skeletal equation 2Mg + O2 ↓ 2MgO balanced chemical equation
Decomposition You start with only one item, but it becomes many General AB ↓ A + B H2O2 ↓ H2O + O2 skeletal 2H2O2 ↓ 2H2O + O2 balanced
General: AB + C AC + B + + Single Displacement Zn Cl Cu Cl Zn Cu Also called single replaced Cations switch places or anions switch Zn Cl Cu + Cl Zn Cu + General: AB + C AC + B
Activity Series Elements can switch places if something more reactive is added, but no reaction occurs if something less reactive is added The activity series gives the order of what can switch K can replace anything in the list Au can be replaced by anything
General: AB + CD AD + CB + + Double Displacement O Mg Ca O Mg Ca Also called single replacement or metathesis Both cations and anions switch S O Mg Ca + O S Mg Ca + General: AB + CD AD + CB