Chemistry Reading

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Chemistry Reading Day (Assignments). (“World of Chemistry”).

Introduction to Matter

Chemistry 11 Welcome to Chemistry

This introductory topic presents a broad overview of chemistry along with a summary of this curriculum. Knowledge of chemistry is useful to almost everyone. Even if we are unaware of it, chemistry occurs all around us all of the time. An understanding and appreciation for chemistry is useful for a broad array of jobs and industries – from healthcare to business roles and even artists. Certainly, chemistry is at the forefront and center of many important aspects of our daily lives. Chemistry is involved with materials we use, energy sources we consume, control of diseases, food supply processes, medicines, and other aspects. Chemistry bridges across the other natural sciences. Chemistry’s relationship with life science, physics, as well as Earth and planetary sciences is evident to science students as they become familiar with the discipline of chemistry. In this set of topics, students will acquaint themselves with a new, microscopic world of wonder – they will identify ways to solve real-world problems – and perhaps most importantly, they will prepare themselves for their own future. (topic)

Chemistry 12 Nature of Matter

In its simplest terms, matter has mass and occupies space. It would be reasonable to call matter “the stuff” which the universe is made up of. Chemistry students become progressively familiar with the atomic nature of matter and the variety of elements and compounds made from them. The states of matter, along with physical and chemical properties – as well as the changing from one state to another – these concepts are among the central themes chemistry students learn regarding matter.   (topic)

Chemistry 13 Properties of Matter

Matter has both physical and chemical properties. Examples of physical properties include color, volume, melting and boiling point, odor, and hardness. A pure substance can be described in terms of its chemical properties. Some examples of chemical processes we see and experience around us are the rusting of various metals, the digestion of food, and the release of energy during the chemical conversion (combustion) of gasoline in our cars.  Earth science students review physical properties  of minerals in Minerals of the Earth (Earth Science topic 17).  Biology students investigate chemical change through how the digestive system converts food into energy for the human body in Physiology (Biology topic 42). Chemistry students learn to recognize types of change (physical and chemical) such as these examples, along with the properties of matter and its potential.  (topic)

Periodic Table Basics

Chemistry 14 The Elements

An element is a substance whose atoms all have the same number of protons. All of a particular element’s atoms have the same atomic number. Elements are chemically the simplest substances and cannot be broken down using chemical reactions. One hundred and eighteen (118) elements are displayed on the periodic table – representing all of the elements in the known universe. Of these, the first 92 are naturally occurring on Earth. The remaining have been “manufactured” in a lab. There are several interesting facts about each of the known elements. For example, oxygen makes up almost half of Earth’s atmosphere, oceans, and crust combined – but nitrogen is 78% of the air we breathe. Carbon is by far the most crucial element to living things, but hydrogen, oxygen, and nitrogen are crucial to cells of living things also. Each element has an interesting story – and purpose. Chemistry students become familiar with groups of like-kind elements and their patterns. All this helps shape our views, and deepens our knowledge and understanding of the world we live in.  (topic)

Chemistry 15 Using the Periodic Table

Most chemistry classrooms have a periodic table hanging on the wall. The chart shows all of the known elements and provides a surprising lot of information about each. The chart – despite its quizzical shape – provides guidance to chemists around the world. Rationale behind its quizzical shape and arrangement of elements becomes increasingly apparent to chemistry students as they progress through further topics. The first column of elements (beginning with H – hydrogen – at the top left) have a similar set of chemical properties. All of them in the first column (except for hydrogen) are called the Alkali metals. The second column is called the Alkaline earth metals. Columns 3 through 12 are called Transition metals. The column on the far right represent the Noble gases. The periodic table is laid out very intentionally in columns and rows. A one-, two-, or three-letter identifier provides a convenient way for chemists to communicate about an element or combinations of elements without using the entire, formal name(s). The numbers (written in sequence from 1 through 118) represent the number of protons in one atom of that element. The number is called the atomic number. These and other important aspects of the period table are covered here.  (topic)

Chemistry 16 Naming Binary Compounds

While there are 118 chemical elements, there many combinations of the elements which make a compound. For our purposes here, a compound is made up of two or more elements. A binary compound is made up of exactly two different elements. This topic introduces the rules in naming a binary compound – that is, naming a compound with exactly two elements.

Early scientists used common names to describe certain elements and compounds. An easy example of this is salt. The expression “salt” in everyday language refers to table salt used to preserve and flavor food. The word salt has been used for many hundreds of years – long before chemistry become a sophisticated science. To chemists, the expression “salt” means something very different than singular meaning of table salt. There are many different salts that are not table salt.

Table salt is sodium chloride (NaCl), a binary compound. Magnesium chloride (MgCl2) is also binary compound and a type of salt. While epsom salt (MgSO4-7H2O) is not a binary compound, it too is a type of salt. There are so many combinations of the elements that it would be impractical (impossible, really) to memorize a simplistic and unique name of every one of the millions of combinations of elements. So instead, there is an agreed upon naming method. You can think of it as a set of rules for naming compounds. In this topic, students become familiar with the rules to name compounds with exactly two different elements. (topic)

Formulas and Units

Chemistry 17 Naming and Writing Formulas

Students become further acquainted with rules and conventions associated with saying the names and writing the names of various compounds. In particular, naming conventions are introduced for several of the most frequently encountered polyatomic ions. Alas, in this instance the names of common polyatomic ions must be memorized. Common names for polyatomic ions are used in much the same way as a single element. As an example, sodium sulfate (Na2SO4) combines the names of sodium (Na, an element) with sulfate (SO4, an ion). Polyatomic ions are charged entities composed of several atoms bound together. Common polyatomic ions (such as sulfate) have special names which students must memorize. (topic)

Chemistry 18 Scientific Notation and Units

Measurements include a numeric value and a units of measure. Most chemistry students have encountered the principles of measurement many times prior to reaching this point. Even so,this topic emphasizes several important aspects of measurement – necessary for applying math skills toward chemistry concepts. Solid mastery of scientific notation and powers of ten provide the basis for many chemistry calculations. Usage of SI units of measure, along with the meaning of various prefixes such as “kilo” and “milli” become crucial to a chemistry student. But further, the application of significant digits, appropriate rounding, and concepts of uncertainty in measurements become important. Students practice conversions, calculations, units of measure, and critical thinking in this topic. (topic)

Chemistry 19 Atoms and Moles

Compared to other subjects, the periodic table and its display of the elements (atoms) serve as a chemistry student’s visual representation of their subject. Similarly, the mole (abbreviated mol) is quite possibly the most important mathematical distinction of chemistry compared to other subjects. Avogadro’s number is a mol, or 6.022 x 1023.   This topic introduces the mole similar to how “dozen” conveys the number 12. Reasons behind usage of the mole, ways to apply it to chemistry calculations, as well as better grasping the smallness of the atom are practiced and discussed. Combining patterns and other information conveyed by the periodic table along with concepts of Avogadro’s number become the foundation of many, more advanced topics in chemistry.  (topic)

Compounds and Solutions

Chemistry 21 Formulas of Compounds

This topic distinguishes between an empirical formula and a molecular formula. Both are used to describe compounds. They are similar in several respects, but they are different from each other. Generally, they serve different purposes. This topic emphasizes empirical formulas. Even so, it is instructive to understand what a molecular formula is – partially for the purpose of contrast. A molecular formula provides the composition of the molecules that are present, whereas an empirical formula expresses the smallest whole-number ratio of atoms present. An example may provide the clearest difference between the two types of formulas.

  • Empirical formula: There are three molecules which have identical empirical formulas. The three molecules in this example are formaldehyde, erythrose, and glucose. Each of these have the same empirical formula which is CH2O. This is the smallest whole-number ratio of atoms present in each of these three compounds. All three molecules have the same ratio of carbon, hydrogen, and oxygen atoms. For every one carbon atom, there are two hydrogen atoms and one oxygen atom.
  • Molecular formula: In contrast, the molecular formulas of these three  molecules are formaldehyde (CH2O), erythrose (C4H8O4), and glucose (C6H12O6). Notice that the molecular formula describes the total number of atoms present (the composition) within their respective molecules.

This topic emphasizes empirical formulas derived through measuring (or, knowing) the mass of various elements in a compound. (topic)

Chemistry 22 Evidence for Chemical Reaction

Not all chemical reactions are visible to the eye. Many chemical reactions signal their change through production of heat (exothermic reaction) – or absorption of heat (endothermic reaction). That said, visible changes often take place too. Examples of visible changes that may (not always) indicate a chemical reaction has taken place are color change, the formation of a solid, the production of bubbles, or a flame occurs. This topic provides students with a grasp of how to identify the characteristics of a chemical reaction – and to learn the information given by a chemical equation. An important skill for chemistry students is in balancing the chemical equation for a reaction. (topic)

Chemistry 23 Reactions in Aqueous Solutions

While this is not intended as a bio-chemistry topic, students should note that most (almost all) of the chemical reactions making life possible take place in aqueous solutions. There are a handful of driving forces chemists use to predict whether such a reaction will take place. Students explore these: formation of a solid, transfer of electrons, formation of water, and formation of a gas. There are notably a variety of ways to classify reactions. Further, there are at least three important ways (equation type) used to describe reactions in solution: molecular formula equations, a complete ionic equation, and a net ionic equation. Because of the importance of reactions in aqueous solutions to life, concepts and techniques presented in this topic apply to a breadth of other scientific principles. (topic)

Chemical Calculations

Chemistry 24 Classifying Reactions

Many chemical reactions involving oxygen produce energy (heat). Such a combustion reaction typically results in a visible flame. Combustion reactions are a type of oxidation-reduction reactions (but, not all oxidation-reduction reactions result in combustion).  Synthesis (or, combination) reactions are another subclass of the oxidation-reduction class of reactions. Decomposition reactions are yet another subclass of oxidation-reduction reactions. Precipitation reactions and acid-base reactions are important categories of reactions that differ from oxidation-reduction reactions. Here, familiarity with types, classes, and subclasses of reaction types is emphasized, along with practice in the identification of these from a written formula. (topic)

Chemistry 25 Using Chemical Equations

Chemistry is really about reactions. Chemical change is a rearrangement of atoms  – as one or more substances change to new substances. Mole-to-mole relationships and mass calculations in particular provide a wealth of information to practicing chemists – and to chemistry students. Applying mathematical ratios, making practical use of scientific notation, and thoughtfully comparing both sides of an equation are important skills for chemistry students to master. (topic)

Chemistry 26 Limiting Reactants and Percent Yield

The limiting reactant (or, limiting reagent) is a reactant in a chemical reaction that determines the amount of product that is formed. Identification of the limiting reactant makes it possible to calculate the theoretical yield of a reaction. Of the reactants involved, the reactant that runs out first – and limits the amount of products formed – is called the limiting reactant.  Using concepts from this topic, students become familiar with important chemistry skills – calculation of percent yield and the theoretical yield of a reaction’s products. (topic)

Mid-Year

Chemistry 27 Energy Temperature and Heat

Energy is power derived from the use of physical or chemical resources. Energy is especially used to provide light and heat or to work machines. Heat (or, thermal energy) is directly related to temperature. While we cannot see individual atoms vibrating, we can feel their kinetic energies as temperature. When there’s a difference between the temperature of the environment and a system within it, thermal energy is transferred between them as heat. Using water as an example, if there is a transfer of energy from hot water to cold water, the flow of energy is called heat. Heat can be defined as a flow of energy due to a temperature difference. Using these concepts, students recognize and categorize chemical reactions where heat flows out of a system (exothermic reaction), and where heat moves into a system (endothermic reaction). (topic)

Chemistry 28 Using Energy in the Real World

Chemistry is connected to other natural sciences. This topic explores an important intersection between chemistry and physics. When we use energy to do work, we degrade its usefulness. Two driving forces of nature include energy spread and matter spread. These driving forces are explained through a tendency in nature scientists call entropy. Entropy is a measure of disorder. As energy spread increases, entropy increases. So too, as matter spread increases, entropy increases. Further, we know from the second law of thermodynamics (an important scientific law in physics), that the entropy of the universe is always increasing. This topic makes connections between chemistry and physics by reviewing the relationship of chemical reactions and entropy. (topic)

Atoms and Bonds

Chemistry 31 Atoms and Energy

Atoms are the small building blocks of all existing substances. They are so tiny that we can’t even observe with our naked eye. Atom is made up of a nucleus, which has protons and neutrons. And there are electrons circling around the nucleus in orbitals. Atoms can emit and receive energy. When atoms receive energy, they become excited. Atoms can also release energy by emitting light. Emitted energy is carried away by a photon. (topic)

Chemistry 32 Atomic Orbitals

Electrons occupy shells around the nucleus of an atom. Electrons move in every direction, but they are limited to their own area, or the orbit that the electron follows, which is what we call shells. Within each shell, there are subshells. Orbitals are regions within an atom that the electron will most likely occupy.

Orbitals within a shell are divided into subshells that have the same value of the angular quantum number . Chemists describe the shell and subshell in which an orbital belongs with a two-character code such as 2p or 4f. The orbital names s, p, d, and f stand for names given to groups of lines originally noted in the spectra of the alkali metals. These line groups are called sharp, principal, diffuse, and fundamental. (topic)

Chemistry 33 Characteristics of Chemical Bonds

In general, strong chemical bonding comes with the sharing or transfer of electrons between the participating atoms. The atoms in molecules, crystals, metals and diatomic gases are held together by chemical bonds. There are two types of bonds; covalent and ionic. Covalent bonds form when atoms share electrons. (topic)

Chemistry 34 Lewis Structures

Lewis structures, also known as Lewis dot diagrams, Lewis dot formulas, Lewis dot structures, electron dot structures, or Lewis electron dot structures (LEDS), are diagrams that show the bonding between atoms of a molecule and the lone pairs of electrons that may exist in the molecule.

The Lewis structure is used to represent the covalent bonding of a molecule or ion. Covalent bonds are a type of chemical bonding formed by the sharing of electrons in the valence shells of the atoms. The atoms in a Lewis structure tend to share electrons so that each atom has eight electrons (the octet rule). (topic)

Basics of Gas

Chemistry 35 Describing the Properties of Gases

Gases have three characteristic properties: (1) they are easy to compress, (2) they expand to fill their containers, and (3) they occupy far more space than the liquids or solids from which they form. There are several basic properties of gases which differentiate gases from liquids and solids: (1) A gas has no definite shape or volume, it will expand to fill its container. (2) A gas is easily compressible. (3) Gases form homogeneous mixtures with each other (without exception). (topic)

Chemistry 36 Using Gas Laws to Solve Problems

Gas laws are the physical laws that describe the properties of gases, including Boyle’s and Charles’ laws.

One of the gas laws chemistry students learn is the ideal gas law. It has four variables. The four gas variables are: pressure (P), volume (V), number of mole of gas (n), and temperature (T). Lastly, the constant in the equation shown below is R, known as the gas constant, which will be discussed in depth further later:

PV=nRT

The  ideal gas law is a good approximation for most gases under moderate pressure and temperature. (topic)

More about Gas

Chemistry 37 Using a Model to Describe Gases

While the most useful of the gas laws is the ideal gas equation, under certain conditions, gases do not obey the ideal gas equation. In particular, at high pressures and/or low temperatures, the properties of gases can deviate significantly from the predictions of the ideal gas equation. This topic begins to address what the characteristics of the individual gas particles are that influence a gas to behave as it does. (topic)

Chemistry 38 Inter-molecular Forces and Phase Changes

Intermolecular forces (IMF) are the forces which mediate interaction between molecules, including forces of attraction or repulsion which act between molecules and other types of neighboring particles – such as atoms or ions. While most substances consisting of small molecules are gases at normal temperatures and pressures, water is a liquid. Why? The answer has to do with intermolecuar forces – those forces which exist between the molecules.

NOTE: intramolecular forces are forces inside the molecules, holding them together – whereas intermolecular forces are between molecules. (topic)

Chemistry 39 Vapor Pressure and Boiling Point

The pressure of vapor present at equilibrium with its liquid is called the equilibrium vapor pressure – or, more commonly – the vapor pressure of the liquid. Vapor pressures of liquids vary widely. Liquids with high vapor pressures are called volatile – that is, they evaporate rapidly. Vapor pressure of a liquid at a given temperature is determined by the intermolecular forces acting among the molecules. There is a relationship between vapor pressure and boiling point of a liquid. This topic explores vapor pressure, and its relationship to boiling point. (topic)

Solids and Solutions

Chemistry 41 Properties of Solids

Most solids contain mixtures of various components. Some naturally occurring solids are almost pure substances. Crystalline solids in particular are explored in this topic. There are three categories of crystalline solids: ionic, molecular, and atomic. Table salt (NaCl) is an example of an ionic solid. Frozen water (frozen H2O) is a great example of a molecular solid. A pure diamond is and example of a solid made from only one type of atom – carbon (C). Several careers-types require a deep understanding of the properties of solids. Some examples of these include material scientists, metallurgical engineers, and crystallographers. (topic)

Chemistry 42 Student Research (Solutions in Industry)

For the purpose of this topic, “solution” shall be defined as a homogeneous mixture of two or more substances in which the molecules or atoms of the substances are completely dispersed primarily in a liquid form at (or, near) atmospheric conditions. This topic is set aside for students to pursue their individual area of interest in regards to the overarching topic of “Solutions.” Students may choose from among the five areas listed here, or with instructor permission, pursue a different angle of solutions based on their individual interest. (1) Solutions in the healthcare-industry. (2) Solutions in the agricultural industry. (3) Solutions in the chemical/oil refining industry. (4) Solutions in the food industry. (5) Solutions in the environment. (topic)

Chemistry 43 Solution Composition & Properties

There are several ways in chemistry to describe the composition of a solution. One way is through a solution’s mass percent. Another, similar way, is to describe a solution’s concentration – often expressed as molarity (M). There are some important conventions chemistry students should become familiar with – such as: solute concentration is always written in terms of the form of the solute before it dissolves. Because math becomes crucial in chemical formulation, conventions like this one become increasingly important as the need for precision increases. A few new terms such as “standard solution” and “dilution” have specific meaning in chemistry. Additionally, some of the new expressions also convey new concepts – such as “colligative property” (a solution property that depends on the number of solute particles present). This topic may initially seem overly concerned with precise meaning and exactness of measurement. And … it is. Especially for students with an eye toward college-level chemistry, this topic introduces ideas that set them up for future success in upper-level chemistry pursuits. (topic)

Chemistry 44 Plasma Gas Liquid Solid (Not)

So far, students have been shown that matter exists as plasma, gas, liquid, or solid. This topic begins to introduce some “not-so-cut-and-dry” categories of matter including non-classical states of matter, low-temperature states of matter, and high-energy states of matter. Students research, explore, and discuss matter which are not as easily categorized: glass, crystals with some degree of disorder, liquid crystal states, microphase-separated matter, magnetically ordered matter, degenerate matter, and superfluids. (topic)

Advanced Topics

Chemistry 45 Acids and Bases

Beyond the general notions of acids and bases introduced in physical science (for example), this advanced review of the topic examines two relevant models: Arrhenius Model, and Brønsted-Lowry Model. Students examine similarities and differences of weak vs. strong acids – and the determination of acidity of a solution. Concepts of titration, the titration curve (also called the pH curve), and discussions of buffered solutions are reviewed.   (topic)

Chemistry 46 Equilibrium

In every-day language, synonyms of “equilibrium” include balance, symmetry, parity, equality, and stability. These every-day words may suggest that “things have stopped – and activity is static.” While it is true the expression equilibrium in chemistry applies to the absence of changes in concentrations of reactants or products – at the molecular level, things are dynamic, not static. Here, students are introduced to the law of chemical equilibrium (once called “the law of mass action”). Changes in volume and/or pressure are examined for their respective impact on equilibrium. Students further familiarize themselves with concepts dealing with solubility and usages of the equilibrium constant (denoted as “K”). (topic)

Chemistry 47 Oxidation-Reduction Reactions

Oxidation is an increase in the oxidation state (a loss of electrons). In contrast, reduction is a decrease in oxidation state (or, a gain of electrons). Students examine how balancing oxidation-reduction reactions can be accomplished by more than one method. In particular, the trial and error method is commonly used as a first-try (this may be called the “inspection method” elsewhere). Another method is “half-reactions.” (NOTE: A half reaction is either the oxidation or reduction reaction component of a redox reaction. A half reaction is achieved/calculated by considering the change in oxidation states of individual substances involved in the reaction). Students briefly review concepts of electrochemistry in the context of both lead storage batteries and dry cell batteries. Students examine the relationship and dependency of these battery types on chemistry’s redox reactions. (topic)

Chemistry 48 Organic Chemistry

This last and final topic lightly introduces generalized concepts associated with the advanced topic of organic chemistry. Often, college-level chemistry begins with a full semester of inorganic chemistry (Chem I) – preceding a semester of organic chemistry (Chem II). Students become acquaint themselves with the importance of carbon (C). Various formulas related to Alkanes and their naming conventions are touched-upon. Contrasts and comparisons of Alkenes and Alkynes are briefly examined. Last, a few conventions for naming Aromatic compounds are introduced. This topic does not aim for application or higher-level considerations of the subject-matter – rather, students should strive to become initially familiar with basic ideas and concepts preparing them for more advanced pursuits at a collegiate level. (topic)

Chemistry 49 End Year Capstone

Knowledge of chemistry is useful to almost everyone. Throughout this course, we have examined that chemistry occurs all around us – all of the time. This understanding and appreciation for chemistry is useful for a broad array of jobs and industries.  Chemistry is at the forefront and center of many important aspects of our daily lives. During this course, students encountered fundamentals of matter and the periodic table, formulas of compounds and solutions, calculation techniques, atoms and bonds, basics of gas, examinations of solids and solutions, as well as a handful of more advanced topics.

Because chemistry is involved with materials we use, energy sources we consume, control of diseases, food supply processes, medicines, and other aspects – chemistry bridges across the other natural sciences. Over this class-year, students have acquainted themselves with a new perspective of the universes microscopic world of wonder.  Perhaps most importantly, they have better prepared themselves for their own future. (topic)

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