Introduction to Chemistry: Matter and Its Properties

• Chemistry delves into matter, its characteristics, and how it undergoes change.

Matter

• Matter possesses mass and occupies space.
• Matter can exist as a solid, liquid, gas, or plasma.
• Atoms constitute the fundamental components of matter.
• Molecules result from the combination of atoms.
• Matter is either a pure substance or a mixture
• Pure substances feature a consistent composition and unique attributes.
• Elements and compounds fall under the category of pure substances.
• Elements cannot be broken down into simpler substances via chemical methods.
• Compounds consist of two or more elements chemically bonded in a specific ratio.
• Mixtures involve the combination of two or more substances while retaining their chemical identities.
• Mixtures are classified as either homogeneous or heterogeneous.
• Homogeneous mixtures exhibit uniform composition, such as saltwater.
• Heterogeneous mixtures have a non-uniform composition, like a mix of sand and water.
• Matter experiences both physical and chemical alterations.
• Physical changes modify a substance's form without affecting its chemical makeup, like ice melting.
• Chemical changes involve rearranging atoms and creating new substances, such as wood burning.

Atoms, Molecules, and Ions

• Atoms represent the smallest unit of an element, maintaining its chemical properties.
• Atoms comprise protons, neutrons, and electrons.
• Protons carry a positive charge, neutrons are neutral, and electrons have a negative charge.
• The atomic number corresponds to the quantity of protons in an atom.
• Isotopes are variants of an element's atoms that differ in neutron count.
• The mass number signifies the total of protons and neutrons within an atom.
• Molecules arise when two or more atoms unite through chemical bonds.
• Chemical bonds are either ionic or covalent.
• Ionic bonds involve the transfer of electrons between atoms, leading to ion formation.
• Covalent bonds entail the sharing of electrons between atoms.
• Ions are atoms or molecules carrying a net charge due to electron gain or loss.
• Cations are ions that have a positive charge.
• Anions are ions that have a negative charge.

Chemical Reactions and Equations

• Chemical reactions entail the rearrangement of atoms and molecules.
• Chemical equations utilize formulas and symbols to depict chemical reactions.
• Reactants are the substances undergoing transformation in a chemical reaction.
• Products are the resulting substances from a chemical reaction.
• Chemical equations adhere to the law of conservation of mass, thereby requiring balance.
• Balancing chemical equations includes adjusting coefficients to equate the number of atoms for each element on both sides.
• Several chemical reaction types exist: combination, decomposition, single replacement, and double replacement reactions.
• Combination reactions involve two or more reactants uniting into a single product.
• Decomposition reactions involve one reactant breaking down into multiple products.
• Single replacement reactions involve one element substituting another in a compound.
• Double replacement reactions involve the exchange of ions between two compounds.

Stoichiometry

• Stoichiometry examines the quantitative relationships between reactants and products during chemical reactions.
• The mole stands as the SI unit for substance amount.
• One mole contains 6.022 x 10^23 entities (Avogadro's number).
• The molar mass signifies the mass of one mole of a substance.
• Stoichiometric calculations employ the mole concept alongside balanced chemical equations to ascertain reactant and product quantities in chemical reactions.
• Limiting reactants are fully consumed during a chemical reaction.
• Excess reactants are present in greater quantities than needed to react with the limiting reactant.
• The theoretical yield represents the maximum product amount achievable from a given quantity of reactants.
• The actual yield represents the product amount obtained from a chemical reaction.
• The percent yield expresses the ratio of actual yield to theoretical yield as a percentage.

Acids and Bases

• Acids are substances that donate protons (H+) or accept electrons.
• Bases are substances that accept protons (H+) or donate electrons.
• The pH scale determines the acidity or basicity of a solution.
• Acids have a pH below 7.
• Bases have a pH above 7.
• Neutral solutions have a pH of 7.
• Strong acids and bases completely dissociate in water.
• Weak acids and bases only partially dissociate in water.
• Acid-base reactions involve proton transfers from an acid to a base.
• Neutralization reactions involve the reaction of an acid and a base to form salt and water.
• Titration measures the concentration of an acid or base in a solution.

Gases

• Gases are a state of matter characterized by their ability to expand to fill available space.
• Gas laws detail the behavior of gases.
• Boyle's law says that gas volume is inversely proportional to pressure at a constant temperature.
• Charles's law says that gas volume is directly proportional to temperature at constant pressure.
• Avogadro's law says that gas volume is directly proportional to the number of moles at constant temperature and pressure.
• The ideal gas law is PV = nRT, where R is the ideal gas constant.
• The kinetic molecular theory elucidates gas behavior based on the motion of gas particles.
• Gases consist of particles in constant, random motion.
• The average kinetic energy of gas particles is proportional to absolute temperature.
• Collisions between gas particles remain elastic.

Equilibrium

• Chemical equilibrium occurs when forward and reverse reactions proceed at equal rates.
• Reactant and product concentrations remain constant at equilibrium.
• The equilibrium constant (K) quantifies the relative amounts of reactants and products at equilibrium.
• Le Chatelier's principle states that a system at equilibrium responds to relieve stress.
• Changes affecting equilibrium include concentration, pressure, and temperature alterations.

Thermodynamics

• Thermodynamics studies energy and its transformations.
• Energy is the capacity to perform work or transfer heat.
• The first law of thermodynamics says that energy remains conserved.
• The second law of thermodynamics dictates that the universe's entropy increases in spontaneous processes.
• Enthalpy (H) is a thermodynamic property that gauges the heat content of a system.
• Exothermic reactions release heat (ΔH is less than 0).
• Endothermic reactions absorb heat (ΔH is more than 0).
• Entropy (S) quantifies the disorder within a system.
• Gibbs free energy (G) combines enthalpy and entropy to predict process spontaneity.
• Spontaneous processes have a negative change in Gibbs free energy (ΔG is less than 0).

Organic Chemistry

• Organic chemistry studies carbon-containing compounds.
• Carbon can form stable bonds, creating numerous organic compounds.
• Hydrocarbons contain only carbon and hydrogen.
• Alkanes are saturated hydrocarbons featuring single bonds.
• Alkenes are unsaturated hydrocarbons containing double bonds.
• Alkynes are unsaturated hydrocarbons containing triple bonds.
• Functional groups dictate the chemical reactions inside molecules.
• Alcohols, ethers, aldehydes, ketones, carboxylic acids, and amines are common functional groups.
• Isomers share a molecular formula but differ in structural arrangements.

This lesson introduces the fundamental concepts of chemistry, focusing on matter and its properties. It covers the different states of matter, the building blocks of matter (atoms and molecules), and the classification of matter as pure substances or mixtures. Homogeneous and heterogeneous mixtures are also discussed.