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

Propiedades y Ensayos de los Metales

Elementos metálicos puros

No se pueden emplear para la fabricación de piezas. Las aleaciones (dos o más elementos) mejoran sus propiedades.

Propiedades de los metales

• Dureza: Oposición al rayado o penetración. Da idea de la resistencia de un material a la deformación permanente.
• Elasticidad: Capacidad de recuperación al cesar la fuerza que los deforma. El límite elástico es la fuerza máxima de deformación.
• Tenacidad: Propiedad que tienen los metales de no romperse. Se opone a la rotura y absorbe la fuerza; da idea de la capacidad que tiene un metal de absorber energía antes de romperse.
• Fragilidad: Facilidad de rotura bajo la acción del choque.
• Fatiga: Resistencia que tiene un material de no romperse

Metals: Properties, Processing, and Applications

Copper

Classification: Density > 5. Danger 5-2, Ultralight < 2.

Advantages: Electrical and thermal conductivity, oxidation and corrosion resistance, low melting point.

Disadvantages: Lower mechanical resistance, more difficult and expensive to obtain.

Sources:

• Native copper: (Poor mineral, not usually found)
• Sulfides: Chalcopyrite and chalcocite
• Oxides: Malachite and cuprite

Characteristics: Reddish, relatively soft, high electrical conductivity, very ductile and malleable, moderate resistance to acids.

Obtaining Process:

• Wet process: Copper < 10%. Diluted sulfuric acid is added to an electrolytic bath.
• Dry process: Copper > 10%. Crushing, grinding, mineral separation, and gangue by flotation

Ketogenesis

Ketogenesis is the biochemical process by which ketone bodies are produced as a result of fatty acid breakdown.

Phase 1: Acetoacetyl-CoA Formation

Acetyl-CoA + Acetyl-CoA → Acetoacetyl-CoA

Phase 2: HMG-CoA Synthesis

Acetoacetyl-CoA + Acetyl-CoA + H₂O → Hydroxymethylglutaryl-CoA (HMG-CoA)

Phase 3: Ketone Body Production

Hydroxymethylglutaryl-CoA (HMG-CoA) → Acetoacetate → Acetone AND β-Hydroxybutyrate

Deamination of Amino Acids

Deamination is the removal of an amino group from an amino acid.

Non-Oxidative Deamination

Serine Complex Unstable → Imino Acid → Pyruvic Acid + Ammonia (NH₃)

Oxidative Deamination

Amino Acid (AA) → Imino Acid → Keto Acid + Ammonia (NH₃)

Glycolysis

Glycolysis is the metabolic pathway that converts... Continue reading "Key Metabolic Pathways and Biochemical Processes" »

Essential Chemical Elements List (H to Pu)

This reference table provides the names and corresponding atomic symbols for the first 94 chemical elements, starting with Hydrogen (H) up to Plutonium (Pu). This list is crucial for students and professionals needing quick access to fundamental chemical nomenclature.

Fundamentos da Termodinâmica

O Que é Calor?

Calor é a grandeza física que mede a energia térmica que passa de um corpo para outro devido à diferença de temperatura entre eles.

Definição de Caloria

Caloria: É a quantidade de calor necessária para elevar a temperatura de 1g de água de 14.5 ºC para 15.5 ºC.

Calor Sensível e Calor Latente

Calor Sensível: Ocorre quando há apenas mudança de temperatura. Ex: aquecimento de um metal.

Calor Latente: Ocorre quando há mudança de estado físico e não de temperatura. Ex: derretimento do gelo.

Calor Específico das Substâncias

Calor Específico: Diferentes substâncias necessitam de quantidades distintas de calor para um aumento de 1 ºC. Ex: Ferro (Fe) = 0.11 cal/g°C. Isso significa que para... Continue reading "Fundamentos da Termodinâmica: Conceitos Essenciais de Calor e Energia" »

XRD for Stress Measurement in Surface Engineering

X-Ray Diffraction (XRD) techniques are employed for stress measurements, particularly in surface engineering. It utilizes Bragg's Law (stated in the source as 2d sin σ, where d is the lattice spacing and σ is related to the diffraction angle; the general form is often 2d sin θ = nλ) and the material's elastic properties to correlate lattice strain with stress values.

Principles and Application

XRD analyzes the diffraction pattern of X-rays interacting with a crystalline material to determine its atomic and molecular structure, including lattice strains which are related to stress.

Advantages of XRD

• Non-destructive
• Fast and simple to perform
• Can be performed in situ (on-site)
• High accuracy for many

National University: Santiago Antunez de Mayolo

Course: General Chemistry

Subject: Introduction to the Periodic System II

School: Agricultural Engineering

Teacher: Victor Martinez Montes

Members:

• Alva Matilla Jesus

1. Title

Chemical Bonding I

2. Aim

• Distinguish how substance properties depend on their type of bond.
• Investigate the linkage present in ionic and covalent substances through the study of electrical conductivity.

3. Theoretical Foundation

The conductivity of a substance is carried by ions—charged particles formed by one or more atoms—excluding metals, whose electrical conduction is not considered in this experiment.

Ionic compounds do not carry current in the solid state, but they do when dissolved or fused, as their crystal lattice releases... Continue reading "Understanding Chemical Bonds and Electrical Conductivity" »

Le Chatelier's Principle

Changes in Concentration

When a quantity of a substance is added to an equilibrium system, it will move to the side where the substance is not present. If, however, we remove one of the substances, the equilibrium shifts to the side where it is located.

Changes in Pressure Affecting Volume

When the pressure is increased from the outside and the system decreases in volume, the equilibrium shifts in the direction where there is a smaller number of moles (or molecules) to counteract the external perturbation.

Changes in Temperature

An increase in temperature always favors the endothermic process, and a decrease favors the exothermic process. If the direct process is endothermic, a temperature increase leads to a higher value... Continue reading "Le Chatelier's Principle and Carbon Chemistry Properties" »

Workplace Safety and Emergency Protocols

1. Types of Fire

• Class A (Solids): Extinguished using water.
• Class B (Liquids): Extinguished with dry powder.
• Class C (Gases): Extinguished with dry powder or versatile dust.
• Class D (Metals): Extinguished with a special powder.
• Class E (Electrical Fires): Extinguished with carbon dioxide (CO2).

3. Fire (Combustion Requirements)

To produce fire, the following elements must align: fuel, combustion (oxygen), heat, and a chain reaction (the fire tetrahedron).

Emergency Management Levels

14. Minor Emergency

An emergency that is easily controlled using the resources available within the company.

15. Partial Emergency

Requires the action of human and material resources located within the building.

16. General Emergency

Requires... Continue reading "Workplace Safety Fundamentals and Emergency Response Protocols" »

Collision Theory

For a reaction to occur, the molecules of the reacting substances must collide. Any factor that increases the collision frequency of such collisions, or increases the probability that these collisions occur with appropriate orientation and possess sufficient energy, will increase the reaction speed.

Reaction Rate ($ ext{V}_{ ext{reaccion}}$): Number of collisions $\times$ time / Molecules of reagents.

Effective Collision

An effective collision requires:

• Appropriate orientation.
• Sufficient energy.

Activation Energy

The Activation Energy ($ ext{E}_{ ext{A}}$) corresponds to the maximum energy reached in the intermediate state of the system, known as the activated complex state. It is the energy needed to move from the reactant state... Continue reading "Chemical Reaction Kinetics and Theories Explained" »