CHEM 121 - General Chemistry I
1) Introduction
Chemistry is always viewed as being the intermediate science and acts as an intermediary
between physics and the other branches of the natural sciences including biology and geology.
Thus, its domain encompasses the range from studying the matter and its properties, and the
processes that take place within the framework of the matter area. Today, there is almost no
aspect of our lives where chemistry is not involved, whether it is in the food we consume, the
water we use, the air we breathe or even in the body itself Chemistry is the science that deals
with composition, structure, properties of substances and the changes they undergo. This is an
informative piece of writing as the overall objective of this particular essay is to explicate the
readers, the general idea about what general chemistry as a branch of chemistry is all about,
treating the reader to an analytic background to the onset of the chemical revolution, the
principles of chemistry, an analysis on how chemical reactions work as well as a look at the uses
of general chemistry. Chemistry can therefore be defined as a way of getting to know the forces
existing globally, properties in different aspects in the world and technologies in the world.
2) Historical Background
` Chemistry from rising out of the mystical to the severe science is a fascinating and rich
tale of man’s desire and logic. Developed by the Egyptian and Greek mystics, alchemy was the
way that demonstrated how it is possible to transmute base metals to noble ones, the famous
philosophers’ stone, the potion of life eternity. Like any science in its early stages, alchemy was
replete with mysticism and things that might not appeal to the modern chemist as pseudo-
science, but principally it was the initiation of chemical experimentation and thus is part of the
foundation of chemistry as practiced today. It is not the same as the beautiful Medieval period
when knights rode in shining armor, or damsels were waiting to be rescued, whereas it became
the Renaissance wherein, at least to some extent, people attempted to use higher methods of
thinking and scientific approach. For instance, Antoine Lavoisier of the latter half of the 18th
century played a role in founding today’s chemistry with assistance in the law of conservation of
mass, along with helping name such lost species as oxygen, hydrogen, and old carbon. It
described the work carried out during the chemical revolution which he had done at that time.
The breakthrough of the periodic table by Dmitri Mendeleev in 1869 just shifted the ground
again: It is important to note that chemical compounds were grouped based on their atomic
weights and on what they could do, which established the foundation for the modern idea and
tendencies of the chemical reaction.
3) Fundamental Concepts
Atomic Structure
Molecules which are made of atoms, and atoms are particles made up of a massive
nucleus containing protons and electrons orbiting in shells around this nucleus. Located in the
center of an atom are basic particles termed nucleus which includes protons bearing positive
charges, neutral neutrons as well as electrons that bear negative charges, these electrons orbit
around the nucleus in shells which are composed of subshells of increasing energy levels. Gilbert
Lewis and Irving Langmuir came up with atomic models that began with Kyle’s solid sphere
model in which Dalton assumed that the atoms are indivisible, and then the plum pudding model
proposed by J. J. Thomson, in which atoms have embedded electrons. One of the most
foundational discoveries that situated the basis for the nuclear model was conducted by Ernest
Rutherford known as the Gold Foil Experiment in 1911. A planetary system model of Niels Bohr
entailing electronic orbits now well defined with quantized values was replaced by the modern
quantum mechanical model developed by Erwin Schrödinger and others that instead of talking of
probabilities of electron orbits just presented probability distribution of electrons.
Periodic Table
The periodic table is a systematic arrangement of the elements in a specific manner based
on the values of their atomic numbers, electronic configuration as well as the periodic nature of
chemical properties. Instead, groups go one under the other, while periods go from left to right;
this is because compounds within the same groups have similar chemical properties given that
the elements have approximately the same number of valence electrons as each other.
Functional trends including: Atomic size, Ionization energy, Electron attachment, and
Electronegativity can be discussed in terms of cyclicity because the electrons are arranged in
different shells and subshells. Such tendencies allow predicting the reactivity and the qualities of
elements as correctly as possible. Similarly, due to the organization of the table by the periodic
law which outlines the nature of elements, the formation of families of the elements contained in
the table is more uniform and includes families like alkali metals, alkaline earth metals,
halogens, and noble gases among others.
Chemical Bonds
Molecules that consist of two or more atoms bonded together by chemical bonds or
which are also known as compounds are very important in the formation of matter. Ionic bonds
occur due to the main forces between oppositely charged ions which are typically when metals
donate their electrons to non-metals. A covalent being is a type of bonding that is brought about
by the sharing of electron pairs amongst non metal atoms resulting to the formation of molecules.
Non metallic bonds may also be combined in a further classification as either polar or non polar
based on the values of electronegativity difference of the bonded atoms. Characteristic of the
metallic bonds is the arrangement in which there are positive ions in a lattice and on outside
them delimited electrons and this is why metals are malleable and good conductors of electricity.
In drawings and formulas, the Lewis structures and the Valence Shell Electron Pair Repulsion
(VSEPR) theory help in determining the shapes and the bond angles of the molecules, which is
important in memorizing the reactivity and the properties of the different molecules.
4) Chemical Reactions
Chemistry is a branch of science that mostly deals with the reactions which are chemical
changes, in which changed substances are formed by chemical elements. These reactions can be
categorized into several types: Combination reactions are the reactions where two or more
elements unite to form a product, decomposition reactions are the reactions where one compound
splits into two or simpler and different substances, substitution (single displacement) reactions
are the reactions in which one element in a compound is replaced by some other element, double
displacement (metathesis) reactions are the reactions where two compounds exchange their ions,
and finally, combustion reaction is the reaction in which substance burns in oxygen
Staichiometry deals with the working behavior of chemical substances and the rearrangement or
striking of the proportion of relative amounts of the reactants and products known as moles
which enables a quantitative estimation or prediction of chemical reactions.
5) States of Matter
Matter exists in distinct states, each with unique properties: Possible phase states include;
solid phase, liquid sample phase, gaseous phase and plasma phase. Solids are one of the forms
of material and at the same time possess certain properties such as shape and volume or any
origin from high compactness of particle’s mass and molecular arrangement and therefore and
forces between the is rather stiff. All these elements are accommodated by a vessel that assumes
the shape of the liquid; the liquid tends to rotate and particles forming the specific volume of the
liquid may be slid or indeed be shifted horizontally in contact with other particles of the same
specific volume. Unlike solids and liquid gases are without the characteristic shape and size and
are composed of particles in continuous and irregular motions which is enclosed in a vessel and
show only a minimal inter-number attraction.
There is another type of light-emitting fluid called plasma which is used in stars and
signs and is an ionized gas containing free electrons and ions of vastly different electrical
characteristics. Phases change through processes like melting and freezing, evaporation and
condensation, sublimation and deposition, all these are Energy forms and may be illustrated in
phase diagrams which are diagrams that show the relationship between temperature and pressure
of a system that contains phases that are at phase equilibrium.
6) Thermochemistry
Thermochemistry is a branch of chemistry that is unique and specialties mostly in energy
transformations during chemical transformations and physical changes. Fundamentally, these
changes are arranged in a manner defined by what is quite well known as the laws of
thermodynamics. Following the first law of thermodynamics or better still the law of energy
conservation there is no way free energy can be created in the universe but rather there are
various ways of changing energy from one form to another or from one body to another body.
Specific heat capacity thus refers to the amount of heat needed to cause a one Kelvin or degree
Celsius change in the temperature of one mole of a material. Whereas entropy (ΔS) is aimed at
showing heat and or changes in temperature, enthalpy (ΔH) is used to describe heat changes at
constant pressure if the reactions were exothermic which releases heat or endothermic, which
suck in heat. From an information science perspective entropy or ΔS gives the measure of about
disorder of the system, and the higher the value of entorp, the more disorder the system
possesses. Gibbs free energy ΔG stands for the fact of the spontaneity of chemical reactions,
enthalpy and entropy being the parameters of the given equation − the negative value of ΔG
confirms the spontaneous reaction, while the positive value of ΔG marks the non-spontaneous
reaction. Thermochemistry is valuable in depicting the energy exchanges accompanying
particular reactions in addition to aiding in the design of efficient reaction processes.
7) Chemical Kinetics
In the subject of chemical kinetics, students can study and understand the rate at which
the reaction takes place as well as the circumstances under which it takes place or controls the
rate of such reactions. Studying the course Reaction kinetics the outcome of the reaction rate
depends on the concentration of reactants, temperature, area of the surface and catalyst running
the reaction. However, from the collision theory point of view, it implies that energy has to be
used to bring the particles in contact with each other and in the right orientation. Often, it is
defined by the activation energy and it is true to the most given fact that the certain reaction
requires a higher amount of activation energy and hence is slow. Kinetic promoters that are
involved in reaction processes and do not participate in the reaction, and influence the need for
supplying low activation energy through various pathways. Knowledge of things like the
mechanism of reaction that gives a clear understanding of the step by step manner in which the
reaction occurs and all the reactions processes that make up the overall chemical change is
helpful in the development of the complex process in which the reactants get transformed to the
final products and on how it would be beneficial or valuable to an industrial or a laboratory
process.
8) Chemical Equilibrium
Chemical equilibrium is reached in a process involving reversible reactions in this
condition where the frequency of forward and backward reactions equals, thus establishing a
standard concentration of reactants and products. This state remains in a constant position as a
given condition termed the equilibrium constant (K) which simply depicts the ratio of the
concentration of the products to the reactants at a given time. Le Chatelier’s Principle is used to
describe the response of a system at equilibrium due to changes in concentration, temperature, or
pressure, as it elicits an effect of the system balancing it back to the state of equilibrium. For
example, it means that when the concentration of reactants is increasing, the position of the
equilibrium shifts toward the product end of the reaction the position of the equilibrium is also
shifted towards the endothermic part of the reaction. For the improvement and better
understanding of reactions, it is crucial to understand equilibrium as shown by the Haber process
of making ammonia and many other biological procedures where reactions are in equilibrium.
9) Acids and Bases
Acids and bases are used for different chemical and other essential functions in the life of
all living organisms and industries. Various definitions exist: On the Arrhenius model, acids are
solutes that yield H ions in solution, and bases are solutes that yield OH ions; By the⁺ ⁻
Bronsted-Lowry framework, acids are the substances that lose protons (H ), and bases lose⁺
electrons (OH ); In Lewis’ model of acids and bases, the acids are defined as the substances that⁻
accept electrons while bases donate them. The pH scale is a technique of ascertaining the acidity
or alkalinity of a soln and the scale involves numerical values ranging from 0 to 14 whereby any
figure 7 is considered as neutral and any figure below 7 is acidic while any above 7 is basic.
Coulometry and Conductometry are instances of Non-quantitative titrations where a reaction
giữa a standard reagent and a solution containing an acid or a base is examined to get the
concentration of a solution. Among those, there is a new topic: buffer solutions, which are
solutions containing weak acids and their conjugate bases and also serving as agents that can
resist changes in pH: they neutralize added acids or base, while keeping the constant pH
significant in both biological and technical processes.
10) Electrochemistry
Electrochemistry deals with the relationship between, electrical energy and chemical
reaction, and among its parts are redox reactions, where oxidation, which refers to electron loss
and reduction whereby an element gains an electron occurs. The Galvanic or voltaic cells are
those in which the chemical energy is transformed into electrical energy like batteries where
normal redox reactions take place and produce electric current. Galvanic cells produce electrical
energy from spontaneous reactions such as those applied in electroplating where a metal is
deposited on a surface through the passing of an electric current through an electrolyte solution.
Electrochemical cells have anodic sites known as anodes, a site where oxidation takes place, and
cathodic sites exposed as cathodes where reduction occurs. Some uses of electrochemistry are
depolarisation and polarisation of batteries, protection of steel and iron from rusting through
cathodic protection, industrial synthesis of chemicals such as chlorine and hydrogen via
electrolysis, and the use of electrochemical detectors in industries for measurement and
regulation.
11) Organic Chemistry
Carbon containing compounds are known as organic compounds and they constitute a
field of study that is incredibly broad in scope and contains millions of known compounds.
Organic compounds containing only hydrogen and carbon are known as hydrocarbons they can
be saturated or unsaturated and they are subdivided into three groups: alkanes , alkenes , and
alkynes. Substituents like alcohols, aldehydes and ketones, carboxylic acids and amines provide
different chemical characteristics or the functionality of the organic compounds. The four major
classes of reactions are substitution, addition, elimination, and polymerization are used as
foundations for synthesizing different types of compounds. Macromolecules meaning giant
molecules are formed of many similar subunits; these are used in items such as plastics, textiles
and biomedical such as heart stints. It will refer to the biomolecules including carbohydrates,
proteins, lipids, and nucleic acids that play diverse roles in life including as energy sources,
frameworks, and for transmitting genetic information.
12) Analytical Chemistry
Analytical chemistry relates to qualitative and quantitative determination of chemicals
and their compositions. It includes qualitative analysis which seeks to establish what is present in
a substance and quantitative being the established amount of a substance present in a given
substance. Methods in analytical chemistry cover for example spectroscopy techniques that
analyze the interaction between light and material to identify a substance; chromatographic
techniques which separate a mixture according to the difference in affinity they possess; and
modern methods such as nuclear magnetic resonance and mass spectrometry which are very
precise identifying molecular data. Through simple and complex sample analysis, these
techniques are compulsory in all research work, quality assurance, environmental analysis, and
forensic science.
13) Applications of Chemistry
Chemistry is a very diverse field that helps to underpin several industries and make
noteworthy technological and social contributions. Chemistry is also crucial in the development
and production of drugs in pharmaceuticals which in turn promotes new treatments and better
health systems. Chemicals assist agriculture to improve on yields and food production through
the use of chemical fertilizers, pesticides, and soil conditioners. Chemistry is used to create novel
substances out of or combined from polymers, ceramics and composites which are utilized in the
construction, electronics and aerospace industries. Environmental chemistry deals with the
problems of pollution, disposal of wastewater, and the implementation of improved methods to
use fewer dangerous compounds and materials and less energy. Chemistry has slowly been
studied and is actively involved in the day to day practice in areas such as food processing and
storage, cleaning substances, body products and other common-use items.
14) Future of Chemistry
Chemistry is a progressive science and a mature science that is moving into new
directions to solve global issues and integrate new tools into the discipline. Nanotherapeutics
that deal with structures below a micrometer can control and arrange substances at a microscopic
level that can afford delivery mechanisms for medicines, electronics and better techniques in
energy storage. Thus, synthetic biology is the art of assembling new biological devices and
systems through engineering new biological components and is mentioned to be akin to
nanotechnology, material science, and technology, and to manifest in diverse fields, including
medicine, food production, energy and other fields. Green process chemistry is the invention of
chemical processes, which is efficient compliance with environmental responsibility, and the use
of resources in the most sparing way possible with reference only to their renewable kinds. Such
developments justify chemistry as a vital area from which solutions to emerging world problems
such as global warming, depleting natural resources, and human health among others call for the
general enhancement of a sustainable and future technologically improved society.
15) Conclusion
General chemistry helps individuals to acquire knowledge on certain assembling and how
it changes and is, therefore, useful in most scientific and technological advancements. Chemistry
started as a seemingly philosophical science and yet has not only advanced over the centuries
and currently but it does affect people’s lives in different ways. In comprehending the chemical
industry and what it turns into, if the basic concepts and theories, kinetic patterns, and static
characteristics, in addition to its applications, are reviewed in detail, students can grasp the
significance of the particular subject to the world and its capacity to answer upcoming issues. As
the whole world introduces new technological changes and increased concern towards
environmental changes and the future, then it will be very meaningful, important, and essential to
embrace and master the role of chemistry in the world as an important tool in addressing
breakthroughs in the search for sustainable solutions in addition to enhancing the understanding
of the physical environment of this world.
