Notes, summaries, assignments, exams, and problems for Chemistry

Synthetic Resins and Polymer Fundamentals

Types of Synthetic Resins

1. Acrylic
2. Vinyl (Vinyl Resins)
3. Acrovinylics
4. Dimethacrylate
5. Epoxies (Epoxy Resins)

Defining Polymers

A Polymer is a high molecular weight macromolecule composed of millions of simple, low molecular weight molecules (monomers) joined into long chains.

Polymer Classification

Polymers are classified:

• According to their structure: Linear chain, branched, and cross-linked.
• According to their chemical composition: Homopolymers, copolymers, and terpolymers.

The Polymerization Process

Polymerization is a process involving a series of chemical reactions where large quantities of simple chain molecules (monomers) join to form one large molecule (polymer). This is typically a fast phenomenon accompanied... Continue reading "Acrylic Resins: Composition, Polymerization, and Properties" »

Noncyclic Photophosphorylation

This process is similar to what occurs after the electron transport chain in the mitochondrial membrane.

• With the stroma, protons are transported to the lumen through the fixed plastoquinone.
• This generates a potential gradient that moves to an enzyme, ATPase, located in F particles, similar to those of mitochondria.
• ATPase uses four protons to phosphorylate ADP to ATP.

Cyclic Photophosphorylation

This occurs when:

• Light striking the plant is between 681 and 700 nm, exciting only Photosystem I (PSI).
• The plant urgently needs ATP, as this process is faster than noncyclic photophosphorylation and does not waste energy reducing NADP when not needed.

The process unfolds as follows:

1. PSI donates electrons to the acceptor chain,

Carboxylic Acids

They are characterized by the group "carboxyl" -COOH at the end of the chain.

They are named by prefixing the word "acid" to the name of the hydrocarbon from which they come, with the ending "-oic". Numerous dicarboxylic acids are named with the ending "-dioic". It is often still used the traditional name, accepted by the IUPAC; many of them are illustrated in the examples below.

When the carboxylic groups are in side chains, they are named using the prefix "carboxyl" and a pager number for that function. In cases where many other acidic groups may also be present, the compound may be referred to as "tricarboxylic", "tetracarboxylic", etc., based on the hydrocarbon from which they come. Place the locators from the carboxyl carbon.... Continue reading "Understanding Carboxylic Acids, Esters, and Amines" »

Electrostatics

Bodies with the same electric charge repel each other, while those with different signs attract.

Key Instruments

• Electroscope: Invented by the Frenchman Jean Antoine, this device detects charged bodies and can be electrified by contact or induction.
• Electrical Pendulum: Used to study the attractions and repulsions between charged bodies.
• Versorium: Invented by William Gilbert, this device detects charged bodies. It is similar to a compass needle, but non-magnetic, and rotates on a vertical axis without friction.

Atomic Structure

Atoms are the fundamental units of chemical elements.

Subatomic Particles

• Electrons: Negatively charged particles within the atom.
• Protons: Particles with a positive charge equal in magnitude to the electron.

Atomic

Electrochemistry and Electrolysis

Electrochemistry studies the transformation between electrical energy and chemical energy. Electrolysis is the decomposition of a substance by means of an electric current.

Classification of Conductors

A conductor is a substance that allows the passage of electric current. They are classified as follows:

• Conductors of the first kind: Metals are characterized by conducting electrical current without changing their structure.
• Second-class conductors: Compounds, either fused or in solution, conduct electric current; however, as the current passes, chemical bonds are broken and the substances are converted into other materials.
• Covalent compounds: These compounds have covalent bonds and do not conduct current.

Industrial

Science Fundamentals

Definition of Science

Science: Is defined as a body of knowledge about the world obtained through observation, experimentation, and razonamiento (reasoning), which follows laws from which testable theories are built.

Branches of Science

• Física (Physics): The science dealing with any change in this area where there is no change in the nature of the substance itself.
• Química (Chemistry): The science that studies the composition, combination, and transformation of substances that affect nature.

Properties of Matter

General Properties

Those whose value does not identify a specific substance. Mass, volume, and the temperature at which a body is found are general properties.

Characteristic Properties

Those that have their own value and... Continue reading "Fundamentals of Science: Physics, Chemistry, and Matter Properties" »

History of the Periodic System

As elements became known, scientists began to classify them based on their properties. This led to several attempts at organization:

Early Classification Attempts

• 1. Metals and Nonmetals

  The earliest distinction was made between metals and nonmetals as more elements were discovered.

• 2. Dobereiner's Triads

  Johann Wolfgang Dobereiner proposed classifying elements in groups of three, known as triads. In a triad, the middle element's atomic mass was approximately the average of the other two, and its chemical properties were intermediate between the elements at the ends.

• 3. Newlands' Law of Octaves (1863)

  John Newlands classified elements in groups of seven. He observed that every eighth element had similar characteristics

Electron Transport Chain

Steps in the Electron Transport Chain

1. Electrons and protons carried by NADH + H⁺ are transferred to FMN, reducing it.
2. FMN is oxidized, transferring its electrons to Coenzyme Q (CoQ), which is reduced. This allows FMN to accept more electrons and continue the chain.
3. CoQ is oxidized and passes its electrons to the next acceptor, a cytochrome. Cytochromes are dehydrogenases.
4. Cytochromes transport protons into the mitochondrial matrix. The chain continues with the electrons.
5. Cytochromes are iron-sulfur molecules. The iron is oxidized (ferric) or reduced (ferrous) Fe. Each iron atom carries one electron, so the process occurs twice.
6. Cytochromes following CoQ in the chain are Cyt b, Cyt c, and Cyt a3.
7. Electrons reach the end of

metallic bond: the bond strength between metal atoms, which owe their stability and properties of metallic lattices. Covalent bonding is the joining of two atoms q comprten one or more pairs of electrons. The salt bridge is the union resulting from the presence of electrostatic forces between positive and negative ions lead to the formation of a compound substituted ionic x a crystal lattice. The covalency of elmento is the number of covalent bonds can form q, which q depends on the number of unpaired electrons. Binding parameters: the binding energy of a diatomic molecule is the enthalpy q occurs when one mole dissociates of molecules in a gas of atoms in the same state. Bond length is the distance between the nuclei of 2 atoms linked by a... Continue reading "Chemical Bond Definitions, Parameters, and Hybridization" »

Classification of Matter

Matter is classified into pure substances and mixtures. Pure substances can be simple (composed of identical atoms) or composite (composed of different atoms). Mixtures are categorized as follows:

• Homogeneous mixtures: These have components that are not easily distinguished (e.g., salt-water).
• Heterogeneous mixtures: These have components that are clearly distinguished (e.g., water and oil).

Physical and Chemical Changes

Physical changes are those in which the nature of the substance does not change (e.g., folding paper). Chemical changes are those in which the substance itself changes (e.g., the oxidation of iron).

Methods for Separating Mixtures

Mixtures, whether homogeneous or heterogeneous, can always be separated by physical... Continue reading "Classification of Matter and Separation Techniques" »