Fenómenos Físicos y Químicos

• Chemical substances are discussed

Physical and Chemical Phenomena

• Physical phenomena don't change a substance's internal structure, e.g., water changing from liquid to steam
• Chemical phenomena do change a substance's internal structure, e.g., combustion and fermentation

Pure Substances: Element and Compound

• A pure substance is formed by only one component, and can be decomposed using chemical methods
• An element is a union of same-type atoms that cannot be broken down into simpler substances by chemical means, but can be separated by nuclear methods
• Examples of elements are Na, H, O, Cl
• A compound is a union of two or more elements with fixed composition, where the elements lose their individual characteristics to gain new specific properties
• Compounds are separated by chemical methods
• Examples of compounds are NaCl (table salt), O₂, H₂O, and C₁₂H₂₂O₁₁ (sugar)

Molecule

• Smallest of a compound
• Retains substance properties
• Examples of molecules are water and ammonia

Mixtures: Homogeneous and Heterogeneous

• A mixture is the union of two or more elements or compounds (pure substances)
• Each component retains its properties
• Mixtures have variable composition and can be separated by physical or mechanical methods
• Homogeneous mixtures don't show distinguishable components/phases, also known as solutions, formed by a solute and a solvent
• Examples of homogeneous mixtures:
• Solid in solid: Alloy
• Liquid in liquid: Seawater, Wine, Soda
• Gas in gas: Air
• Solubility-based classification of solutions include saturated solutions, unsaturated solutions, and supersaturated solutions
• Saturated solutions have the maximum amount of solute that can dissolve at the standard pressure and temperature
• Unsaturated solutions contain less solute than a saturated solution
• Supersaturated solutions contain more solute than a saturated one
• Heterogeneous mixtures display distinguishable components/phases, clearly formed by various substances
• Example of heterogeneous mixture: salt and sand, or gravel and cement

Atomic Structure

• Atom is the fundamental matter particle that participates in a chemical reaction, it cannot be divided into smaller portions, and is composed of subatomic particles
• Neutron: A neutral subatomic particle found in the atom's nucleus
• Proton: A positively charged subatomic particle found in the atom's nucleus
• Electron: A negatively charged subatomic particle that orbits the nucleus
• Atomic Number (Z): Represents the protons in an atom, which equals the number of electrons in a neutral atom
• Mass Number or Atomic Mass (A): The number of protons plus neutrons in an atom's nucleus
• Number of Neutrons: Mass number (A) minus atomic number (Z)
• Isotopes: Atoms with the same atomic number but different mass numbers, therefore, same number of protons but varying number of neutrons
• Ion: An atom with an eletrical charge
• Cation (+): Loses electrons
• Anion (-): Gains electrons
• John Dalton's atomic hypothesis (1808), which marked the start of modern chemistry, considers the atom to be the fundamental particle of matter that can associate with other atoms to form molecules
• Elements are made of tiny, indivisible particles called atoms
• All atoms of an element are identical in mass and size
• Atoms of different elements vary in mass and size
• Chemical compounds are formed by combining atoms of different elements
• Atoms form compounds in simple numerical ratios in various relations, e.g., 1:1, 2:1, 2:3
• J.J. Thomson proposed the "plum pudding" model (1897) where the cathode rays are affected when influenced by electric and magnetic fields and are considered negatively charged particles
• His atomic model represents atoms made of electrons that move around on a uniform mass of positive electricity

Atomic Orbitals

• Ernest Rutherford concluded that the atom has a nucleus with the positive charge and mass of the atom, with electrons dispersed throughout mostly empty space
• Niels Bohr:
• Electrons orbit the nucleus in specific paths
• Electrons neither gain or lose energy, when they maintain the same energy level
• Electrons that orbit, don´t irradiate energy, if this was to occur, they would hit against the nucleus
• Electrons can absorb or emit energy, losing and gaining energy

Atomic orbitals

• Represents the space occupied by an electron in an atom
• An electron can be found within different energy levels, or can be numbered using quantum number prinicples
• Principal quantum number (n) determines the main energy level in which the electron is located
• Azimuthal quantum number (l), determine the sub - levels inside the energy levels, these numbers dictates the orbitals shape
• Magnetic quamtum number (m), represents the location where the electrons are located (orbital) and dictates their spatial position
• Spin quantum number (s), indicates the spin rotation of the electron, is represented by the following numbers -1/2 and +1/2
• Orbitals or space region; The regions of energetic space of electronic probabilistic demonstrations, are represented in the following schemes

Electronic Configuration

• The most stable distribution of electros

Periodic table

• Organize by atomic number
• By Physical and chemical traits
• Elements are classified as metals, metalloids, non metals

Classification by periods or families

• Elements are divided by columns showing the numbers of electron in the final energy level
• elements are shown by horizontal rows

Valence

• Combines when winning or losing electrons according to the octet rule
• Valence: indicates amount of external electrons when is in a chemical bond
• Octet role: An elements will present eight electrons in its final energy level

Lewis Structure

• The periodic table group shows the numbers of electrons in the final energy level
• The are represented by dots

Periodic table properties

• Electronegativity: it is the propriety of the atom to attract electrons in a bond
• Table shows the trend when losing or gaining electrons

Ionization potential

• Is the energy neccesary to sepparate the external electron in an aislated atom
• An element loses ionization potential when increasing the atomic number

Links

• Forces that join 2 atoms or more to function as a unit

Ionic Bonds

• Non-metal element plus a mealt
• Metal transfers the electron to the non Metal
• Present crystalline structure

Covalent bonds

• Joining non metallic elements that share electrons

Polar Covalent bond

• Non Metallic Elements with different electronegativity is carried

Non polar covalent bonds

• Joining idénticas non-metallic elements that share elcetrones
• Doesn´t exist water solubility

Coordinate Convalent link

• Occurs with the unión of two atoms by a pair of electrons
• Is equal from several Points of view as the convalent link

Inorganic Elements classification

• Through the Pauli tabla is possible classify bonds in the following Way:

• 1.8 ionic link

• <1.8 convalent polar link
• Without Diference: convalent

Types of compound

• Oxides
• Basic
• Acid
• Acid
• Base
• Salts: are a mixture between acid base

Mol

• Number of molecules in oxigen in 32 Grams
• Number of molecules contained in the molécular weight is measured in grams
• To the atomic mass, divided for the masa of atom is known as Avogadro numbers

Molecular weight Calcus

• Depends on the number of molecules and grams
• Follow the fórmula M= m/ PM

Composition, Structure, and Contamination

• Polarity and Hydrogen Links: Water exist in molecules of 2 hydrogen and 1 oxygen átomos though covalent links: the angle is 104.5°
• Oxigen attracts with more force its negative and positive
• Creates an intermolecular attractive forcé

Physical traits

• Physical traits of water are the following
• No color, smell, flavor
• Freezes st 0° C
• Boils at 100° C
• Density of 1g/ml

Chemical traits

• Good diluyente for acid base reactions
• Main source for Hydrogen prearation
• Reacts with soluble oxides of the metals

Contamination

Physical conatmination

• Can be solids and have natural origins
• Most are synthetic and enter the water From humans
• Affects appereance
• Restrict animal Life
• Compounds are organinc or non-origanic

Chemical contamination

• Salts of metal are such as clourides and sulfatos
• Comes from the animal sector
• Can be gases

Biological contamination

• Bacteria that provoque illness

Ácidos, Bases, and electrolitos

Acid Base theory

• Acids: Sour flavour, corrosive with metal, and the skin
• Bases: Caustic in the skin, dissolbable in water

Arrhenius theory

• Acids: Creates the HO ions
• Bases: Dissociates in HO ions

Classification by conductivity power

• Ácidos fuertes: se ionized with gran facilidad
• Ácidos débiles: does not ionized easily

Compuestos ácidos y Básicos

• Acid salts: Formed by substitution of hydrogen
• Basic salts: Formed by óxido substitution

Potencial of hydrogen (pH)

• Is defined ad the ionization number of the H
• Ionized in hydro ions and hydroxide
• Kw = [HO] [OH] -14
• pH + poh= 14
• pH=-logs [H]

Classification by pH

• Scale from 1 to 14
• Indicares can change color dependent on the color
• Can be many problems related
• Electrolitos All fluid contain the ions dissolved

Solutions

• Electrolytes - is composed by fluids that allow dissolving
• Electrolytes are called such of the electricity allow the flowing electrical current
• No electrolitos does NOT allow running of electrical current
• Concepto of solvent: Solvent: Substance en more proportion
• Solute: is a substance in minor proportion and molecule dispersion
• Concentration: depends on the solute quantity is added

Air

• it is a mixture of gases that haves been evolving, and sustaining the animal Life
• Made of mostly of NITROGEN and Oxígen and other componentes
• Has oxygen that reacts when combustion reaction occures
• The conbustion is when a cómpound reacts with the Oxygen

Incomplete combustion

• carried our form fósiles and créate carbono monoxide

Oxide Formation

• Basic Oxide formation: metal +oxygen
• Acids oxide Formation: no metal + oxygen

Oxide reduction REactions

• Reactions between Metal and no metal with an electrons Transfer
• Oxidación: When losing electrons
• Reduction: when winning electrons
• the oxidation number indicates the combination of the Elements and the electrons quantity lost, ganar or shared

Contaminants of air

• alters the Physicall and chemical proprerties
• divided in primaries and secundaries
• Primaries: Remanes in the atmosphere from the start
• oxide of Azufre se produces cuándoelemental azufre se burns, se burns with bacteria .
• el so4
• Oxigens contamination interfers
• The monoxide transfers oxygen to the organism
• carbonic dioxide has some phenomenos such as: green house effect, cause of increasing the temperature

Contamination

• Secondaries are contaminations subject to reactives from the átmosphere
• Ozone: When is foros de The estratosfera se previene solar rays from entering
• Chlorofloro carbons are for coolant
• Smoke from quimic reactions