Notes, summaries, assignments, exams, and exercises for Chemistry for Other courses

Homologous Series

A series of organic compounds having similar structures and similar chemical properties in which the successive members differ in their molecular formula by -CH₂ group.

The different members of the series are called homologous.

Characteristics of Homologous Series

All the member of a homologous series can be described by a common general formula.

Example: All alkane can be described by the general formula C_nH_2n+2.

Each member of a homologous series differ from its higher and lower neighbouring members by a common difference of -CH₂ group.

Tissue Homogenization and Protein Extraction

Tissues are rich in proteins that fulfill different functions and therefore possess different characteristics. Depending on these traits, it is possible to solubilize, separate, and purify them through various methods.

Methods for Cell Disruption

The first step in the extraction of most proteins and subcellular structures is the disruption of tissues or cells to obtain a cell lysate. In this lysate, the protein or multiprotein complex subcellular structure is kept in conditions that permit isolation. This is accomplished using procedures commonly known as soft mechanical homogenization.

These methods produce the rupture of cell membranes gently, thereby releasing the cellular contents. Common techniques...

The Nature of Matter and Its Changes

Chemistry is the scientific discipline dedicated to studying the nature of matter and the changes affecting its composition and properties.

Physical vs. Chemical Changes

• Physical changes do not alter the fundamental nature or chemical identity of substances. Examples include melting ice or boiling water.
• Chemical changes (or chemical reactions) result in the formation of new substances with different chemical properties. Examples include burning wood or rusting iron.

Classifying Matter

Pure Substances

A pure substance has a definite and constant composition, characteristic physical and chemical properties, and cannot be separated into other substances through physical methods.

Mixtures

A mixture has a variable composition...

Demineralization of Brackish Water by Electrodialysis

This detailed explanation covers the process of demineralization of brackish water using Electrodialysis (ED), based on standard water chemistry concepts.

Brackish Water Characteristics

Brackish water contains dissolved salts, with salinity levels higher than freshwater but lower than seawater. It tastes salty and is generally unsuitable for drinking or industrial use. To make it potable, salts must be removed (desalination).

Electrodialysis Principle

Electrodialysis is an electrochemical desalination process. When an electric field is applied, ions (salts) in the water migrate through specialized ion-selective membranes:

• Cation-exchange membranes: Allow only cations (e.g., Na⁺, Ca²⁺, Mg²⁺)

Calculating Coal Calorific Value

Calculate the net and gross calorific value of a coal sample with the following composition: C = 82%, H = 8%, O = 5%, N = 1.4%, and ash = 3.5%.

Step 1: Calculate the Gross Calorific Value (GCV)

Dulong's formula is used to calculate the GCV based on the percentages of carbon (C), hydrogen (H), and oxygen (O) in the coal sample. The formula is:

GCV = 1/100 [8080C + 34500(H - O/8) + 2240S]

Assuming no sulfur (S) is present (not listed in the composition):

GCV = 1/100 [8080(82) + 34500(8 - 5/8)]

GCV = 1/100 [662560 + 34500(7.375)]

GCV = 1/100 [662560 + 254437.5]

GCV = 916997.5 / 100

GCV = 9169.975 kcal/kg

Step 2: Calculate the Net Calorific Value (NCV)

The NCV is calculated from the GCV by subtracting the latent heat of condensation...

Eye Conditions: Myopia and Hyperopia

Myopia

Myopia occurs when the eye has excessive convergence, focusing light from distant objects in front of the retina, resulting in blurred distant vision. This condition is corrected with diverging lenses.

Hyperopia

Hyperopia occurs when the eye is less convergent than normal, causing images of nearby objects to form behind the retina, leading to blurred near vision. This condition is corrected with converging lenses.

Fundamentals of Nuclear Physics

First Model of the Nuclear Atom

The atom consists of a nucleus, which contains almost all of its mass and all of its positive charge. Electrons orbit the nucleus at some distance. The nuclei are formed by two types of particles called nucleons: protons and neutrons....

Raoult's Law and Distribution Law

• Raoult's Law: Describes the relationship between vapor pressure and the mole fraction of a solvent.
• Distribution Law: Describes the distribution of a solute between two immiscible liquids.

Complexation Classification and Measurement

• Classification: Complexes can be classified as coordination, molecular, or inclusion complexes.
• Methods of measurement: Include spectrophotometry, chromatography, and titration.

HLB and Sorensen pH Scales

• HLB Scale: Measures the hydrophile-lipophile balance of a surfactant.
• Sorensen pH Scale: Measures the pH of a solution using a logarithmic scale.

Aerosols and Inhalers

• Aerosol: A suspension of fine solid or liquid particles in a gas.
• Inhaler: A device used to deliver medication to the lungs.

Understanding Chemical Bonding Principles

Chemical bonding is the union between atoms, molecules, or ions to form larger structures. Molecules, in turn, can be joined by intermolecular forces to form multimolecular structures.

The Octet Rule

To form a stable molecule or structure, atoms that bond tend to gain, lose, or share electrons to complete their valence shell with eight electrons.

Types of Chemical Bonds

Ionic Bond

The ionic bond originates as a result of electrostatic forces exerted between oppositely charged ions, thus forming an ionic crystal. This typically occurs between elements with very different electronegativities.

Covalent Bond

The covalent bond between two atoms occurs when these atoms share electrons so that they complete their...

Stoichiometry and Fixed Ratios

Fixed Ratios in Building and Manufacturing

Describe an experience you’ve had making or building something where the amount of each ingredient or building block came in fixed ratios.

Building a model airplane is an example. For each model, there must be two wings and three wheels. In order for the model to look correct or work properly, there must be a certain, unvarying number of wings and wheels.

Direct Arithmetic Units in Chemical Problems

A chemical problem may be presented to you in units of moles, mass, or volume. Which one of these can be directly used in your arithmetic no matter what the conditions are?

Moles can be directly used. The number of molecules or moles is the basic unit used in solving chemical...

Atomic Structure and Isotopes

Proton number: The number of protons in an atom (and the number of electrons in an uncharged atom).
Nucleon number: The total number of protons and neutrons in an atom.

In the periodic table, moving one element to the right increases the proton number by 1. Moving one element down increases the proton number by 8 in the first three periods (excluding transition elements).

Isotopes and Radioactivity

Isotopes: Atoms of the same element that have different numbers of neutrons (e.g., Carbon-12 and Carbon-14).

• Non-radioactive isotopes: Stable atoms.
• Radioisotopes: Unstable atoms that decay and emit radiation.

Applications of Radioisotopes

• Medical: Cancer treatment (radiotherapy) using Cobalt-60 to kill cancer cells.
• Industrial: