chemistry homework help

chemistry homework help

Exploring the Fundamentals of Chemistry: A Comprehensive Guide for Students

1. Introduction to Chemistry

The first matter that was studied, of any kind, was air (pneuma) by the Greeks. Greek philosophy was the root of all sciences, so it is natural that the early chemical discoveries came from Greece. At that time, it was difficult to differentiate between air and fire, and it seemed that air might be the one thing in the world that remained the same in every material. Later named “elements,” it was believed that air, water, earth, and fire existed in simple forms. Galileo (1608) went to Venice, and the barometer was discovered by him; Santorio measured a time change in blood mass. Linnaeus (1707-1778), a Swedish naturalist, was the first to introduce binomial nomenclature of the genus and species of organs. J. K. Dobereiner (Germany) in 1829 noted that atomic weights of some elements shared common characteristics, for example, calcium, strontium, barium.

Chemistry is often referred to as the “central science” because of its subject matter, which deals with the behavior and basic composition of matter in the world around us. A working definition of chemistry that I like is: “Chemistry is the study of matter and the changes it undergoes.” What does this mean? Chemistry is often thought of as simply being an area of science that deals with different chemicals and chemical processes, and that is a reasonable reflection of what chemistry encompasses. The changes that are referred to in our working definition include explaining how different kinds of matter are formed by combining or reacting one substance with another, and in many cases, releasing different characteristics of matter when these substances are brought together. Chemistry has many diverse sub-disciplines or ways of studying the changes in matter, but fundamentally, it is the science that examines and tries to understand these changes. Humans have studied and worked with chemistry for a very long time, and a history of chemistry is often ascribed to the “alchemy” work of the ancients.

2. The Periodic Table and Chemical Elements

Chemical elements are any substance containing only one sort of atom, and cannot be separated any simpler using chemical means. Each element on the periodic table presents a number of properties, such as their behavior as a solid, liquid or gas at room temperature, and the appearance or form of their atoms. The element will also have a range of different physical and chemical properties such as softness, malleability, hardness, color, and many others. Some of the properties that can be identified in the elements on the periodic table becoming periodic trends include atomic radius, ionization energy, electron affinity, electronegativity, and metallic character. It is important to recognize how the periodic table is organized and what each element contains within its structure as a fundamental stepping stone into the world of chemistry. Finally, the inclusion of new elements in quantum chemistry and theoretical designs, such as atomic number 119 and onwards, would lead to an expected continuation of the periodic table and the need to expand on its currently known form.

The periodic table of elements has been around for over 150 years, but it is still being added to as more elements are confirmed. The periodic table is a way of organizing the specific properties of chemical elements in an organizational table that showcases information held in one specific element property – the atomic number. It was first debuted by Dmitri Mendeleev in 1869 with a table of elements that would be considered a rudimentary precursor. The mechanisms of the periodic table demonstrate that the properties of the elements either follow a specific pattern or they repeat periodically – which is where the name “the periodic” table of elements comes from. The periodic table also provides the ability to thoroughly understand and interpret the behavior or specific properties of elements. It also helps to unveil the relationship between elements and the periodic trends as they follow across each period and group in the table. The table also organizes chemical elements into groups and subgroups. The activities and functions of elements, and the formation of chemical compounds can also be properly understood when using the table as a reference.

3. Chemical Bonding and Molecular Structure

Forces existing between the atoms Bonding in a molecule is strong, which results in a large amount of energy released during the time of formation. However, force exists between the neighboring molecules also. This is known as intermolecular forces. Depending upon the nature of the bond, style of elongation, type of force, and style of arrangement – nature of bond, whether the polymer is linear/bi-linear branched, whether the compound is conducting/non-conducting or water-loving, or it’s not at all depending on a lot of bond formation that we have read, we are looking through the eyes of bonding in all little little. Things which differentiate the one substance of chemical properties have become a topic of discussion in the chain.

Arrangement of atoms in a molecule Again, by dealing with the atoms, we see each atom contribute a certain number of electrons for the formation of a chemical bond. The number of electrons is distributed and arranged in such a way which is nearest to the minimum value of energy and maximum stability. Geometry, shape, size, length of bond formed, angle of bond formed, bond order, bond length, inter-atomic distance, inter-nuclear distance, inter-planar distance, nature of bond, properties of bond, protective nature of bond, anti-bonding nature of the bond, behavior of the bond, presence of sigma/pi/bridge bond, etc. tell a lot about how the bond has been formed, in what direction, and what amount of energy is required to completely break the bond.

Formation of a Chemical bond It includes the nuclei and the inner shell electron part of the atoms in a molecule, viz. chemical bond is the attractive force which holds the appropriate atoms together in a molecule. There are 3 types of chemical bonds – covalent, ionic, and metallic. These bonds also tell about the properties of the compounds, whether it is conducting/non-conducting, soluble in water/not, hardness, melting point, boiling point, etc.

Willard Gibbs divided the entire energetic aspect of the universe into two parts – energy and entropy. Energy is the capacity to do work, while entropy is the second driving force which dictates the change in the spontaneous direction. Our fundamental goal in this chapter is to understand chemical bonding, that is, how the atoms combine and arrange in a molecule. The subject can be broadly divided into two parts:

Chapter 3: Chemical Bonding and Molecular Structure

4. Chemical Reactions and Stoichiometry

Chemical reactions – rearrangement of atoms that convert reactants into products – are based on a few fundamental laws and principles: the law of conservation of matter; knowledge of reactants and products; balanced equations and stoichiometry. These quantify the relationships among all substances involved in chemical reactions. Stoichiometry focuses on the amounts, compositions, and proportions of reactants and products in chemical reactions, leading directly to the quantitative relationships between reactants and products for computing their masses or volumes. This is the basis of gravimetric or volumetric analysis. Balancing chemical equations is a useful mental exercise that allows the learner to know how the different compounds and elements will interact in a given chemical reaction, but little more. In order to perform useful, quantitative studies, the balanced chemical equation must be interpreted in terms of moles of the reactants and the products.

Anyone interested in an introduction to chemistry will eventually come face-to-face with the term stoichiometry. When chemical reactions occur, it might be important to know how much product will be formed given a certain amount of reactant or the amount of starting material necessary to synthesize a desired quantity of product. Somehow, the mathematical guidelines that allow such a prediction are summarized in the term “stoichiometry”. Before proceeding to discuss why stoichiometry cannot be simply deduced from a balanced equation, we need to modify the concept of a chemical reaction, making it more reliable and suitable to describe practical observations (also distinguishing between stoichiometric reactions and real-world ones). Of course, we will then show how to balance the reaction and how to use a balanced reaction to make predictions based on stoichiometry.

5. Acids, Bases, and pH

In the second year of this program, you studied in detail equations showing the reaction of an acid with a base. These are called acid-base titrations. So far, we used the concepts and shared additional information, calculations, and examples appropriate for those who have studied acid-base titrations. Perhaps it’s useful to review these topics when you study for exams or want to give it another try. When you have time, it’s also a good idea for you to learn and understand the buffer concepts. Buffers are common chemistry laboratory items. A buffer solution is one that resists any appreciable change in its pH.

Brønsted-Lowry acids and bases are related to the pH scale. A scale developed by Søren Sørensen, defining the pH of a solution as the negative of the base 10 logarithm of the concentration of the H+ ions, is called the Sørensen scale. A pH value of 7 indicates that it is a neutral solution since the concentration of H+ ions is equal to the concentration of OH- ions in the water. A pH below 7 is considered an acid, while a pH above 7 is a base.

This theory is used to describe the donation or uptake of a proton. As proposed by these two scientists, an acid is especially prone to releasing a proton, while a base is especially prone to taking up a proton. When an acid releases a proton, it generates the corresponding base. That is, for the reaction HA(aq) → A-(aq) + H+(aq), A- is called the conjugate base of acid HA, while H+ is called the conjugate acid of base A-. The substance HA, having the ability to donate a proton, is called a protic acid. The Brønsted-Lowry bases are the same as what we have seen in the Arrhenius definition. That is, the OH- ion is a Brønsted-Lowry base when combined with a proton to form water.

Acids and bases play a significant role in systems we encounter in many contexts, from our own stomachs to the environment and biological systems. One theory used to define an acid and a base is the Brønsted-Lowry theory.