Unit 5: Chemical Reactions

Synthesis React

ion

Reactants

• Reactants are two element

• Neither of the reactants are aqueous

Products

• Use the charges to determine the formula

• If the compound is ionic → solid

• If the compound is molecular → solid, liquid, or gas

Decomposition

Reactants

• Compound

Product

• Two elements

• Identify it element is diatomic

• Use periodic table to find state of matter

• Balanced equation

Combustion

Reactants

• An element or hydrocarbon reacts with O₂(g)

Products

• If reactant is element, use rules of synthesis

• If reactant is hydrocarbon (C_xH_y), the products are always H₂O(g) and CO₂(g)

Balancing trick: its often that that the coefficient is a full number (ex:7.5), so multiply the whole ratio by x2

Single Replacement

Only occurs when the free element is more reactive than the element it replaces

• Metal replaces metal and hydrogen

• Non-metal replaces non-metals

• Hydrogen replaces metal

The compounds on the product or reactant side are always aqueous

Double Replacement

When two aqueous compounds exchange ions

→ If the reactant compound is unsoluble (solid) then it cant break apart into to

Double replacement reaction will occur if

• Both reactants are aqueous

• At lest on product is a solid, gas, or water

• If both products are aqueous then no reaction occurs