Parts of an Equation Types of Reactions IPC Notes Parts of an Equation Types of Reactions

What is a chemical reaction? A chemical reaction is the act of changing substances into new substances. The products of the reaction have different chemical and physical properties.

A Chemical Equation Instead of writing down the entire sentence “hydrogen reacts with oxygen to form dihydrogen monoxide (water)”, you could write the chemical equation.

2H2 + O2c2H2O REACTANTS → PRODUCTS

5 Parts of a Reaction reactants – the substances that exist before a reaction takes place; found on the left side of the equation

5 Parts of a Reaction products – the substances that exist after a reaction takes place; found on the right side of the equation

5 Parts of a Reaction subscripts – show the number of atoms in a chemical formula ex) H2O

5 Parts of a Reaction coefficients – show the number of formula units in an equation 2H2 + O2 → 2H2O

5 Parts of a Reaction yield sign – the arrow that separates the reactants from the products

Other Symbols in an Equation (s) = substance is solid (l) = substance is liquid (g) = substance is a gas (aq) = substance is dissolved in water

Other Symbols in an Equation D = heat A formula written above or below an arrow means it is a catalyst (a substance that speeds up a reaction without being used up by it.)

Types of Reactions Synthesis Decomposition Single replacement There are 5 types of reactions Synthesis Decomposition Single replacement Double replacement Combustion

Synthesis Reaction A synthesis reaction occurs when two or more reactants combine to form a single product. It will follow the form: A + B a AB Example: Fe + S a FeS

Decomposition Reaction A decomposition reaction occurs when one reactant breaks down into two or more products. It will follow the form: AB a A + B Example: CaCO3aCaO+CO2

Single Replacement Reaction One element replaces another element in a compound. Generally follows the form: AB + C a A + BC Example: Mg+Zn(NO3)2aZn+Mg(NO3)2

Double Replacement Reaction Two compounds create two new compounds as the product. Generally follows the formula: AB + CD a AD + CB Example: Na2S+Cd(NO3)2aCdS+2NaNO3

Combustion Reaction A compound reacts with oxygen producing energy in the form of heat and light. Usually, it is a hydrocarbon reacting with oxygen, and the outcome is always carbon dioxide and water.

Combustion Reaction Follows the form: A + O2 a CO2 + H2O Example: CH4 + O2 a CO2 + 2H2O

2Na + 2H2O a 2NaOH + H2 Single Replacement

Fe + S a FeS Synthesis

Al(OH)3 + 3NaCl aAlCl3 + 3NaOH Double Replacement

2PbO2 a 2PbO + 3O2 Decomposition

Ba(CN)2 + H2SO4 a BaSO4 + HCN Double Replacement

C3H8 + 5O2 a 3CO2 + 4H2O Combustion

4Li + O2 a 2Li2O Synthesis

2Ag + 2HCl a 2AgCl + H2 Single Replacement

2H2O2 a 2H2O + O2 Decomposition

C2H2 + O2 a CO2 + H2O Combustion

2HBr a H2 + Br2 Decomposition

CrSO4 + 2AgNO3 a Cr(NO3)2 + Ag2SO4 Double Replacement