In this lesson our instructor talks about basic concepts of chemistry. First, he discusses solids, liquids, and gases. He talks about the general characteristics and particulate-level drawing of each one. Then he lectures on classification of matter, pure substances, mixtures, physical changes, and chemical changes. He ends the lesson with three helpful sample problems. Basic Concepts of Chemistry Chemistry can broadly be defined as the study of matter and its changes. The (3) physical states of matter are solids, liquids and gases. Matter can undergo both physical and chemical changes. Matter can exist as elements, compounds, or as homogeneous and heterogeneous mixtures. Physical properties tend to be measurable and/or related to senses, while chemical properties describe reactivity.
In this lesson our instructor talks about tools in quantitative chemistry. First he discusses units of measurement, percent error, standard deviation, precisions, and accuracy. Then he talks about significant figures, uncertainty, identifying significant figures, using significant figures in calculation, and dimensional analysis. He ends the lesson with a summary and one helpful sample problem. Tools in Quantitative Chemistry Dimensional analysis is the use of conversion factors to convert between different units, including the standard SI units of measurement. Percent error is related to accuracy, while standard deviation is related to precision. Significant figures are related to precision, and must be considered when performing calculations. Significant figures are a relate to a measurement’s uncertainty.
In this lesson our instructor talks about atoms, molecules, and ions. First, he discusses the atomic structure, isotopes, the periodic table, ionic compounds, and molecular compounds. Then he talks about the mole, percentage compositions, empirical and molecular formulas. He ends the lesson with a summary and two helpful sample problems. Atoms, Molecules, and Ions Rutherford’s gold foil experiment suggested the presence of the nucleus. Protons and neutrons reside inside the nucleus, while electrons are outside. Isotopes are atoms of the same element with different number of neutrons. The mole allows for conversion to/from number of units of anything. Dalton’s law of multiple proportions is demonstrated when solving for empirical and molecular formulas.
In this lesson our instructor talks about chemical reactions. First, he discusses the law of conservation of mass and balancing chemical reactions. Then he talks about balancing chemical reaction, chemical equilibrium, electrolytes and nonelectrolytes. He also lectures on predicting the product of an aqueous reaction through single-replacement, and double-replacement. He ends the lesson with a summary and two helpful sample problems. Chemical Reactions The need to balance chemical reactions follows from the law of conservation of mass. Electrolytes or electrolytic solutions contain free ions in solution. Strong electrolytes dissociate completely, while weak electrolytes hardly ionize. When predicting if a precipitate will form during an aqueous reaction, it is useful to refer to a table of solubility rules. A net ionic equation only shows the formation of the nonaqueous species from its constituent ions.
In this lesson our instructor talks about chemical reactions. First, he discusses the Arrhenius definition, the bronsted-lowry definition, and the autoionization of water. Then he talks about oxides of metals and nonmetals, and oxidation-reduction reactions. He ends the lesson with a summary and three helpful sample problems. Chemical Reactions II Arrhenius acids ionize in water to form H+ and an anion, while Arrhenius bases ionize to form hydroxide and a cation. Bronsted-Lowry acids donate a proton to water, while Bronsted-Lowry bases accept a proton from water. The (7) strong acids dissociate completely in water. A neutralization reaction between a Bronsted-Lowry acid and base always yields a salt and water. There are several chemical aqueous reactions that form a gas byproduct. Oxidation-reduction, or redox, reactions involve a transfer of electrons and a change in oxidation number.
In this lesson our instructor talks about stoichiometry. First, he discusses mole to mole ratios and mass to mass conversion. Then he talks about limiting reactants and percent yields. He ends the lesson with a summary and three helpful sample problems. Stoichiometry I Stoichiometry uses coefficients from a balanced chemical equation as a conversion factor to relate any (2) reactants and/or products. Mole to mole ratios are central to any stoichiometry problem. The limiting reagent or reactant dictates how much product is expected to form (known as the theoretical yield). Molarity expresses solution concentration, and can be used as a conversion factor. Acid-base titrations are used to determine (or standardize) the concentration of an unknown solution.
In this lesson our instructor talks about stoichiometry. First, he discusses molarity and dilutions. Then he talks about the double-displacement precipitation reactions, neutralization reactions, and acid-base standardization. Lastly, he lectures on experimental setup and an example on acid-base standardization. He ends the lesson with a summary and two helpful sample problems. Stoichiometry II Stoichiometry uses coefficients from a balanced chemical equation as a conversion factor to relate any (2) reactants and/or products. Mole to mole ratios are central to any stoichiometry problem. The limiting reagent or reactant dictates how much product is expected to form (known as the theoretical yield). Molarity expresses solution concentration, and can be used as a conversion factor. Acid-base titrations are used to determine (or standardize) the concentration of an unknown solution.
In this lesson our instructor talks about gases. First, he discusses the kinetic molecular theory of gases, parameters to characterize gases, and the simple gas laws. Then he talks about the ideal gas law, applications of the ideal gas law, gas pressures, partial pressures, and gas stoichiometry. He ends the lesson with a summary and two helpful sample problems . Gases The Kinetic Molecular Theory of gases are (5) postulates which describe gas behavior. Any gas that is assumed to follow this theory is called an ideal gas. A series of gas laws relates the gas parameters pressure, temperature, volume and moles to each other holding all else constant. The ideal gas law can be used to interpret gas density and its relationship with temperature. We can apply stoichiometry techniques to reactions involving gases.
In this lesson our instructor talks about intermolecular forces and liquids. First, he discusses intermolecular forces of polar molecules and intermolecular of nonpolar molecules. Then he talks about properties of liquids. He ends the lesson with a summary and two helpful sample problems. Intermolecular Forces & Liquids The main types of IMF are ion-induced dipole, dispersion, dipole-dipole, and hydrogen bonding. IMF can exert strong influence on a liquid’s physical properties, such as boiling point and vapor pressure. By using IMF, we can make a strong educated guess of the relative volatility of a liquid.
In this lesson our instructor talks about the chemistry of solids. First, he discusses the basic structure of solids, crystal lattices, and lattice enthalpy. Then he talks about different types of crystalline solids, phase changes involving solids, and the phase diagrams. He ends the lesson with a summary and three helpful sample problems. The Chemistry of Solids The common unit cells for solids are primitive cubic, body-centered cubic, and face-centered cubic. The unit cell structure can influence a solid’s density and texture. Lattice energy is used to quantify the strength of the interaction within a crystalline solid. Phase diagrams are used to graphically predict a substance’s physical state at a set of pressure and temperature conditions.
In this lesson our instructor talks about energy and chemical reactions. First, he talks about the first law of thermodynamics, calculating ∆U, Q, and W, and constant-volume calorimetry. Then he discusses constant-pressure conditions, calculating enthalpy, phase changes, heats of reaction, and using standard enthalpies of formation. He also lectures on enthalpy from a series of reactions and coffee-cup calorimetry. Energy & Chemical Reactions State functions are path-independent. The first law of thermodynamics states that energy is conserved during a chemical reaction. Energy can be transferred through heat and work. Calorimetry problems involve either constant-volume or constant-pressure scenarios. Enthalpy is the amount of heat transferred under constant pressure.
In this lesson our instructor talks about structure of atoms. First, he discusses electromagnetic radiation, atomic spectroscopy, and the Bohr model. Then he talks about the wave nature of matter, quantum mechanics, and the shape of atomic orbitals. He ends the lesson with a summary and two helpful sample problems. Structure of Atoms Light is a form of electromagnetic radiation which can be described by its energy, wavelength, and frequency. The Bohr Model, which gives a simplistic view of photoemission, incorrectly assumed that electrons traveled in fixed, circular orbits around the nucleus. The advent of quantum mechanics resulted from the idea that matter has both a wave-particle nature. Heisenberg’s Uncertainty Principle states that we can never know the exact location of a moving electron. Schrodinger helped develop wavefunctions, giving rise to the concept of the atomic orbital.
In this lesson our instructor talks about periodic trends. First, he discusses the electron configuration of atoms and atomic radii. Then he talks about ionic radii, ionization energy, and electron affinity. He ends the lesson with a summary and two sample problems. Periodic Trends A consequence of quantum mechanics was the establishment of certain periodic trends, including ionization energy, electron affinity, atomic size and electronegativity. The periodic table is very organized and informative concerning an element’s physical and chemical properties. An atom’s electron configuration can be determined following the Aufbau Principle. Orbital box diagrams are drawn following the Pauli Exclusion Principle and Hund’s Rule.
In this lesson our instructor talks about bonding and molecular structure. First, he discusses types of chemical bonds, electronegativity, bond polarity, and Lewis electron dot structure of atoms. Then he talks about resonance, formal charges, VSEPR theory, molecular polarity, and bond properties. He ends the lesson with a summary and a helpful sample problem. Bonding & Molecular Structure Lewis structures are depictions of covalent bonding in molecules and ions. Formal charge can be used to help construct the best Lewis structures for any molecule/ion. Using VSEPR theory, a Lewis structure can be used to predict molecular geometry and molecular polarity.
In this lesson our instructor talks about valence bonding theories. First he discusses spᶟ hybridization, sp² hybridization, and sp hybridization. Then he talks about molecular orbital theory. He ends the lesson with two helpful sample problems. Advanced Bonding Theories Valence bond theory can explain for observed bond angles via hybrid orbitals, but doesn’t always account for a compound’s magnetic behavior. MO theory is a delocalized bonding model, and views electrons as being distributed throughout the entire compound. An MO diagram can be used to predict magnetism and bond order for a molecule.
In this lesson our instructor talks about solutions and their behavior. First, he talks about units of concentration, like dissolves like, and factors affecting solubility. Then he talks about colligative properties. He ends the lesson with a summary and two sample problems . Solutions & Their Behavior Solution concentration can often be expressed in units of molarity, molality, weight percent, or as ppm. Polar solutions are miscible with other polar solutions, and nonpolar solutions are miscible with other nonpolar solutions. Polar and nonpolar solutions do not mix and form hetereogeneous mixtures. The solubilities of gases and solids in a solution are influenced by pressure and temperature. Colligative properties are independent of a solution’s identity and are dependent on the relative amount of solute.
In this lesson our instructor talks about chemical kinetics. First, he discusses rate laws and methods of initial rates. Then he talks about integrated rate laws, reaction mechanisms, reaction rate, temperatures, and catalysis. He ends the lesson with a summary and two helpful sample problems . Chemical Kinetics Kinetics studies the factors that can influence the rate of a chemical reaction. The method of initial rates and the use of integrated rate laws can help solve for the rate orders and for the rate constant. The slowest step of a reaction mechanism dictates the overall reaction rate. The Arrhrenius equation relates the temperature of a reaction directly to its reaction rate.
In this lesson our instructor talks about principles of chemical equilibrium. First, he discusses the equilibrium constant, heterogeneous equilibria, manipulating K, and the reaction quotient Q. Then he talks about le Chatlier's principle, and problem solving with ICE tables. He ends the lesson with a summary and two helpful sample problems. Principles of Chemical Equilibrium Chemical equilibrium is a dynamic process, having equal rates of the forward and reverse reactions. The equilibrium constant describes the extent to which products are formed over reactants. Le Chatelier’s Principle states that when a system at equilibrium is disturbed, it will react to restore equilibrium. ICE tables can be used to calculate equilibrium concentrations or pressures.
In this lesson our instructor talks about acid-base chemistry. First he discusses quantifying acid-base strength, writing out acid-base equilibria and salts solutions. Then he talks about diprotic acids, polyprotic acids, Lewis acids, Lewis bases, molecular structure, and molecular acidity. He ends the lesson with a summary and two helpful sample problems. Acid-Base Chemistry Bronsted-Lowry acid-base chemistry involves a loss/gain of a proton to/from water. Conjugate pairs only differ by one proton and are inversely related in terms of acidity/basicity. Acidity and basicity can be quantified primarily via pH, Ka ,pKa and percent ionization. The structure of a molecule can have a significant impact on how acidic it can be. ICE tables are easily applied to an acid-base equilibrium situation.
In this lesson our instructor talks about applications of aqueous equilibrium. First, he discusses calculating pH of an acid-base mixture. Then he talks about buffers, buffers preparation and capacity. He also lectures on acid-base titrations, solubility equilibria, and complexation equilibria. He ends the lecture with a summary and one helpful sample problem. Applications of Aqueous Equilibria Equilibrium can be applied to various systems, including acid-base mixtures, buffers, titrations, solubility, and complex ion formation. The Henderson-Hasselbalch equation can be used to approximate the pH of a buffer system. Titration curves monitor pH versus volume of titrant added. Solubility product constants quantify the extent to which an ionic solid is soluble in water.
In this lesson our instructor talks about entropy and free energy. First, he discusses entropy, heat flow, and the second law of thermodynamics. Then he talks about the third law of thermodynamics, problem-solving involving entropy, and Gibb's free energy. He ends the lesson with a summary and three helpful sample problems. Entropy & Free Energy Nature favors states of low energy and high entropy. Entropy is related to disorder or chaos, and is the focus of the second and third laws of thermodynamics. There are a series of equations that allow us to calculate both entropy andGibb’s free energy under a given set of conditions.
In this lesson our instructor talks about electrochemistry. First, he discusses redox reactions, voltaic cells, and electrochemical potentials. Then he talks about the Nernst equation, Gibb's free energy and electrochemistry. He also lectures on charge, current, and time. He ends the lesson with a summary and two helpful sample problems. Electrochemistry Electrochemistry studies how chemical energy can be produced and converted into mechanical energy, which in turn can perform work such as powering an electrical device. A potential is produced when there is a transfer of electrons from the reducing agent to the oxidizing agent which can happen in neutral, acidic, or basic media. The Nernst equation allows for determination of the cell potential when not at standard conditions.
In this lesson our instructor talks about the chemistry of transition metals. First, he discusses coordination compounds, nomenclature of coordination compounds, and structures of coordination compounds. Then he talks about isomers of coordination compounds, electronic structure, and implications of electronic structure. He ends the lesson with a summary and two helpful sample problems. The Chemistry of The Transition Metals Coordination compounds contain a central metal atom/ion attached to ligands, which may be atoms and/or molecules. Coordination compounds are often observed with coordination numbers of 4 or 6, giving tetrahedral, square-planar, and octahedral geometries. A set of rules exists for nomenclature (naming) of coordination compounds. Crystal-field theory can explain both the color and magnetism of coordination compounds.
In this lesson our instructor talks about nuclear chemistry. First, he discusses types of radioactive decay such as alpha decay, beta decay, and gamma decay. Then he talks about nuclear equations and nuclear decay. He ends the lesson with a summary and two helpful sample problems. Nuclear Chemistry Nuclear reactions involve a change of chemical composition and can be accompanied by substantial amounts of energy. The energy released can be in the form of alpha, beta, and gamma rays, with gamma rays being the most harmful and penetrating. Writing and balancing a nuclear equation follows the law of conservation of mass and charge. Radioactive decay processes follow first-order kinetics.
In this lesson our instructor talks about basic concepts of chemistry. First, he discusses solids, liquids, and gases. He talks about the general characteristics and particulate-level drawing of each one. Then he lectures on classification of matter, pure substances, mixtures, physical changes, and chemical changes. He ends the lesson with three helpful sample problems. Basic Concepts of Chemistry Chemistry can broadly be defined as the study of matter and its changes. The (3) physical states of matter are solids, liquids and gases. Matter can undergo both physical and chemical changes. Matter can exist as elements, compounds, or as homogeneous and heterogeneous mixtures. Physical properties tend to be measurable and/or related to senses, while chemical properties describe reactivity.