Fundamentos de Química Geral Cheat Sheet

Key Definitions

• Ligações Químicas: Interactions that hold atoms together in compounds.

• Geometria Molecular: 3D arrangement of atoms in a molecule.

• Polaridade: Distribution of electrical charge over atoms in a molecule.

• Forças Intermoleculares: Forces between molecules affecting physical properties.

• Ácidos e Bases: Substances that donate (acids) or accept (bases) protons.

• Leis Ponderais: Principles governing mass relationships in chemical reactions.

• Massas e Mols: Molar mass relates mass of substance to amount in moles.

• Fórmulas Químicas: Representation of chemical substances using symbols.

• Balanceamento de Equações: Ensuring the number of atoms is equal on both sides of a reaction.

Important Concepts

Ligações Químicas

• Iônicas: Transfer of electrons between atoms.

• Covalentes: Sharing of electrons between atoms.

Geometria Molecular

• VSEPR Theory: Shapes determined by electron pair repulsion.

• Common Shapes: Linear, trigonal planar, tetrahedral, octahedral.

Polaridade

• Polar Molecules: Unequal sharing of electrons (e.g., H₂O).

• Nonpolar Molecules: Equal sharing (e.g., CO₂).

Forças Intermoleculares

• Dipolo-Dipolo: Between polar molecules.

• Forças de Van der Waals: Temporary dipoles in nonpolar molecules.

• Ligação de Hidrogênio: Strong dipole-dipole interaction involving H.

Key Formulas

• n: number of moles

• m: mass of substance (g)

• M: molar mass (g/mol)

PV = nRT

• P: pressure (atm)

• V: volume (L)

• n: moles

• R: ideal gas constant (0.0821 L·atm/(K·mol))

• T: temperature (K)

Common Mistakes to Avoid

Common Mistake: Confusing covalent and ionic bonds in terms of electron transfer.

Memory Tricks

Tip: "LEO the lion says GER" — Loss of Electrons = Oxidation, Gain of Electrons = Reduction.

Key Diagrams

   H
   |
H--C--O--H
   |
   H

     O
    / \
   H   H