Understanding Chemical Reactions: A Comprehensive Guide

The Law of Conservation of Mass

Matter cannot be created or destroyed. The number of atoms in the reactants must be the same as the products. Atoms don't appear or disappear, they just rearrange. (Hence why you have to balance out chemical equations)

Balancing Equations

• The subscripts in the chemical formula cannot be changed (The little number beside a formula that is part of it).
• Use coefficients to balance.
• Coefficients multiply the entire compound by that number (4PO = 4P 4O).

Example: N₂+O₂>N₂O = 2N₂+O₂>2N₂O

Balancing Word Equations

• Determine what the reactants and the products are, convert names to chemical formulas. (Individual elements that are diatomic (molecular) will be, S₈, P₄, I₂, Br₂, Cl₂, F₂, O₂, N₂, H₂) If it's not diatomic just write it on its own with no charge (monatomic)

Example: Lithium phospate > lithium+phosphorus+oxygen

4Li₃PO₄>12Li+P₄+8O₂

Example: 2Fe+6HBr>2FeBr₃+3H₂

Iron and hydrobromic acid react to form Iron (III) bromide and hydrogen gas

Carbon Dioxide is CO₂, Water is H₂O

Acids

Hydro+ic = Ide, ic = ate, ous = ite

Organics

1 meth, 2 eth, 3 prop, 4 but, 5 pent, 6 hex, 7 hept, 8 oct, 9 non, 10 dec (Propane = (H=2n+2) Propane = C₃H₈)

Molecular

1 mono, 2 di, 3 tri, 4 tetra, 5 penta, 6 hexa, 7 hepta, 8 octa, 9 non. 10 deca (Second word ends in ide)

Types of Chemical Reactions

• Synthesis/Combination A+B>AB
• Decomposition AB>A+B
• Single Displacement A+BC>B+AC (three elements)
• Double Displacement AB+CD>CB+AD (Four elements)
• Combustion CH+O>CO₂+H₂O (Water, carbon dioxide, oxygen)
• Acids And Bases HA+BOH>BA+H₂O (Has H and OH)

Collision Theory

Atoms and molecules must collide into each other to bond.

• Pressure: Higher the pressure higher the rate (Same atoms, less room)
• Temperature: The higher the temperature the higher the rate
• Catalyst: Speeds up the reaction by lowering the activation energy for a successful bond)
• Concentration: Higher the concentration higher the rate (oxygen, same room more atoms)
• Surface Area: The more surface area the higher the rate

Gas does not do surface area, solid does not do pressure Slow chemical reaction rate is rust, fast chemical reaction rate is fire.