Introduction to Chemistry

• Chemistry involves studying matter, its characteristics, and how it transforms.
• Matter possesses mass and occupies space.

Branches of Chemistry

• Analytical Chemistry focuses on the composition of substances.
• Biochemistry studies chemical processes within living organisms.
• Inorganic Chemistry studies substances lacking carbon.
• Organic Chemistry studies carbon-containing substances.
• Physical Chemistry studies the physics underlying chemical processes.

States of Matter

• Solids maintain a definite shape and volume.
• Liquids maintain a definite volume but assume the shape of their container.
• Gases lack a definite shape and volume.
• Plasma constitutes an ionized gas.

Chemical Properties

• Flammability signifies the ability to burn.
• Reactivity signifies the ability to undergo chemical change.
• Corrosiveness signifies the ability to destroy or damage other substances.

Physical Properties

• Color represents the visual aspect of a substance.
• Density represents mass per unit volume.
• Hardness represents resistance to scratching or denting.
• Melting Point signifies the temperature at which a solid transforms into a liquid.
• Boiling Point signifies the temperature at which a liquid transforms into a gas.

Chemical Change

• Involves the creation of new substances.
• Examples include burning wood, rusting iron, and cooking an egg.

Physical Change

• Preserves the substance's identity.
• Examples include melting ice, boiling water, and cutting paper.

Elements

• Elements cannot be broken down into simpler substances via chemical means.
• Elements consist of only atoms with the same number of protons.
• Represented by chemical symbols (e.g., H for hydrogen, O for oxygen).

Compounds

• Compounds can only be separated into simpler substances by chemical means.
• Compounds consist of two or more elements chemically combined in fixed proportions.
• Examples include water (H₂O) and salt (NaCl).

Mixtures

• Homogeneous mixtures exhibit uniform composition (e.g., saltwater).
• Heterogeneous mixtures lack uniform composition (e.g., sand and water).
• Mixtures can be separated via physical means.
• Mixtures consist of two or more substances physically combined, not chemically bonded.

Atoms

• Composed of protons, neutrons, and electrons.
• Protons carry a positive charge and reside in the nucleus.
• Neutrons have no charge and reside in the nucleus.
• Electrons carry a negative charge and orbit the nucleus.
• Atoms represent the smallest unit of an element retaining its chemical properties.

Atomic Number

• Atomic number determines the identity of an element.
• Atomic number represents the number of protons in an atom's nucleus.

Mass Number

• Mass number represents the total count of protons and neutrons in an atom's nucleus.

Isotopes

• Isotopes exhibit the same atomic number but different mass numbers.
• Isotopes represent atoms of the same element with varying neutron counts.

Ions

• Cations possess a positive charge (lose electrons).
• Anions possess a negative charge (gain electrons).
• Ions are atoms or molecules that have gained or lost electrons, acquiring a net electric charge.

Molecules

• Molecules can consist of the same element (e.g., O₂) or different elements (e.g., H₂O).
• Molecules consist of two or more atoms bonded together through chemical bonds.

Chemical Bonds

• Ionic Bonds arise from the transfer of electrons between atoms.
• Covalent Bonds arise from the sharing of electrons between atoms.
• Metallic Bonds, found in metals, feature delocalized electrons.
• Chemical Bonds represent the forces binding atoms together in molecules or compounds.

Chemical Reactions

• Reactants are the starting materials.
• Products are the substances formed.
• Chemical Reactions rearrange atoms and molecules to create new substances.

Balancing Chemical Equations

• Adheres to the law of conservation of mass.
• Ensures equal atom counts for each element on both sides of the equation.

Stoichiometry

• Used to calculate amount of reactants/products.
• Stoichiometry studies the quantitative relationships between reactants and products in chem rxns.

Moles

• One mole contains Avogadro's number (6.022 x 10²³) of particles.
• The mole is the SI unit for the amount of substance

Molar Mass

• Molar mass is expressed in grams per mole (g/mol).
• Molar mass signifies the mass of one mole of a substance.

Solutions

• Solute is the substance being dissolved.
• Solvent is the substance doing the dissolving.
• Solutions are homogeneous mixtures of two or more substances.

Concentration

• Molarity (M) represents moles of solute per liter of solution.
• Concentration signifies the amount of solute dissolved in a given amount of solvent or solution.

Acids

• Have a pH less than 7.
• Taste sour.
• Acids are substances that donate protons (H⁺) in aqueous solutions.

Bases

• Have a pH greater than 7.
• Taste bitter and feel slippery.
• Bases either accept protons (H⁺) in aqueous solutions or release hydroxide ions (OH⁻).

pH Scale

• Ranges from 0 to 14, with 7 denoting neutrality.
• The pH scale measures the acidity or basicity of a solution

Neutralization Reactions

• Acid-base reactions result in the formation of a salt and water.

Oxidation-Reduction Reactions (Redox)

• Oxidation represents the loss of electrons.
• Reduction represents the gain of electrons.
• Redox involves the transfer of electrons between species.

Organic Chemistry

• Carbon can form stable bonds with itself and other elements, giving it unique properties
• Organic Chemistry studies carbon-containing compounds.

Functional Groups

• Alcohols (-OH), carboxylic acids (-COOH), and amines (-NH₂) are examples.
• Functional groups dictate the characteristic chemical reactions of molecules.

Polymers

• Polymers include plastics, proteins and DNA.
• Large molecules made up of monomers.

Chemical Thermodynamics

• Studies energy and its transformations in chemical reactions.

Enthalpy

• The sum of its internal energy and the product of its pressure and volume.
• Thermodynamic property of a system.

Entropy

• Measure of randomness or disorder in a system.

Gibbs Free Energy

• Thermodynamic potential is used to predict spontaneity of a reaction.

Periodic Table, Periodic Properties, Variations of Properties, and chemical bonding.