Study Notes on Chemistry and Biological Compounds

Matter

  • Composed of anything with mass and occupying space.

  • States: Solid (definite shape & volume), Liquid (definite volume, changeable shape), Gas (changeable shape & volume).

Energy

  • Capacity to do work (kinetic vs potential).

  • Forms: Chemical, Electrical, Mechanical, Radiant/Electromagnetic.

  • Energy conversions often lose some energy as heat.

Composition of Matter

  • Elements: Unique substances not broken down chemically.

  • Atoms: Building blocks for elements; represented by atomic symbols (e.g., C, Na).

  • Properties: Physical (detectable senses) vs Chemical (interaction of atoms).

Major Human Elements

  • Carbon (C), Hydrogen (H), Oxygen (O), Nitrogen (N).

  • Lesser elements include Calcium (Ca), Phosphorus (P), Potassium (K), etc.

  • Trace elements are needed in minute amounts.

Atomic Structure

  • Nucleus: Contains neutrons (no charge) and protons (positive charge).

  • Electrons orbit nucleus (negative charge).

Models of the Atom

  • Planetary Model: Electrons in fixed orbits.

  • Orbital Model: Electron probability regions around nucleus.

Identification of Elements

  • Atomic number = number of protons.

  • Mass number = sum of protons and neutrons.

  • Isotopes: Atoms with same protons but different neutrons; Radioisotopes undergo decay.

Molecules and Compounds

  • Molecule: Two or more atoms; Compound: Different kinds of molecules bonded.

Mixtures and Solutions

  • Mixtures: Physically intermingled components.

  • Solutions: Homogeneous mixtures with solutes and solvents.

Chemical Bonds

  • Electrical shells house outermost electrons; forms bonds.

  • Valence shell: Outermost energy level (octet rule).

  • Types of bonds: Ionic (transfer electrons) and Covalent (share electrons).

Chemical Reactions

  • Involves formation/breaking of bonds; may be reversible.

  • Types: Combination, Decomposition, Exchange, Redox reactions.

Enzymes

  • Catalysts composed of proteins; specific in function; lower activation energy.

Overview of Matter and Energy

  • Matter: Defined as anything that has mass and occupies space. It exists in three states: solid, liquid, and gas.

  • Energy: The capacity to do work. Major forms include chemical (stored in bonds), electrical (movement of charged particles), mechanical (moving matter), and radiant (electromagnetic waves).

  • Energy Conversion: Potential energy becomes kinetic energy; however, conversion is inefficient, often releasing heat.

Atomic Structure and Subatomic Particles

  • Elements: Basic chemical substances (e.g., Oxygen, Carbon) comprised of atoms.

  • The Nucleus: Found at the center, containing Protons (p^+) with a positive charge and Neutrons (n^0) with no charge.

  • Electrons (e^-): Negatively charged particles that orbit the nucleus in specific energy levels or shells.

Identification and Calculation

  • Atomic Number: Represents the number of protons. In a neutral atom, this also equals the number of electrons.

  • Mass Number: The sum of protons and neutrons (Mass Number = p^+ + n^0).

  • Isotopes: Varieties of an element with the same number of protons but different numbers of neutrons.

Chemical Bonding and Valence

  • Valence Shell: The outermost electron shell which determines chemical reactivity.

  • Octet Rule: Atoms generally interact to achieve a stable state of eight electrons in their valence shell (except for the first shell, which holds two).

  • Ionic Bonds: Formed by the transfer of electrons from one atom to another, resulting in charged ions.

  • Covalent Bonds: Formed by the sharing of electrons between atoms to achieve stability.

Chemical Reactions and Catalysts

  • Reaction Types: Synthesis (building), Decomposition (breaking down), and Exchange.

  • Redox Reactions: Key in energy production; involves the transfer of electrons (Oil Rig: Oxidation is Loss, Reduction is Gain).

  • Enzymes: Specialized proteins that act as biological catalysts to speed up reactions by lowering the required activation energy.