Matter, Elements, and Compounds

• Material is classified into substances, mixtures, elements and compounds, and atoms and molecules.
• A substance has a defined (constant) composition and distinctive properties.
• A mixture contains two or more substances that retain their distinctive properties.
• An element is a substance that cannot be separated into simpler ones by chemical means, with 118 known elements.
• A compound consists of atoms of two or more elements chemically bonded together.

Properties of Matter

• Physical properties can be measured and observed without altering the composition or identity of the substance.
• Chemical properties require a chemical change to be observed.
• Extensive properties depend on the amount of matter being considered.
• Intensive properties do not depend on the amount of matter.

Dalton's Atomic Theory:

• Elements consist of extremely small particles called atoms.
• Atoms of the same element are identical in size, mass, and chemical properties, while atoms of different elements are different.
• Compounds are formed from atoms of more than one element, with a simple whole number or fractional ratio between the atoms of any two elements in a compound.
• Chemical reactions involve only the separation, combination, or rearrangement of atoms, not their creation or destruction.
• Proust's Law of Definite Proportions states that different samples of the same compound always contain the same elements in the same mass proportion.
• Dalton's Law of Multiple Proportions states that if two elements can combine to form more than one compound, the masses of one element that combine with a fixed mass of the other are in a ratio of small whole numbers.

Conservation of Mass

• Matter is neither created nor destroyed, only transformed.
• The atomic number (Z) is the number of protons in the nucleus of an atom of an element.
• The mass number (A) is the total number of neutrons and protons in the atom of an element.
• Number of neutrons can be calculated by subtracting the atomic number (Z) from the mass number (A).
• Periods are horizontal rows, and groups or families are vertical columns in the periodic table.
• Categories of elements include metals, nonmetals, and metalloids.
• A molecule is an aggregate of at least two atoms in a definite arrangement held together by chemical forces (chemical bonds).
• An ion is an atom or group of atoms with a net positive or negative charge due to the loss or gain of electrons.
• A cation is a positive ion that has lost electrons.
• An anion is a negative ion that has gained electrons.
• An ionic compound is formed by cations and anions.

Redox Reactions

• Oxidation-reduction (redox) reactions involve the transfer of electrons.
• Oxidation involves the loss of electrons.
• Reduction involves the gain of electrons.
• A reducing agent donates electrons.
• An oxidizing agent accepts electrons.

Oxidation Number

• Oxidation number (oxidation state) is the number of charges an atom would have in a molecule or ionic compound if electrons were completely transferred.
• Loss of electrons results in oxidation, which increases the oxidation number.
• Gain of electrons results in reduction, which decreases the oxidation number.

Chemical Bonding

• A covalent bond is formed by two atoms sharing a pair of electrons.
• In a polar covalent bond, electrons spend more time around one atom than the other.
• Polar covalent bonds typically occur between nonmetals with different electronegativities (0.1 – 1.9).
• An ionic bond is the electrostatic force that holds ions together in an ionic compound, typically between a metal and a nonmetal, with an electronegativity difference of 2.0 or more.
• A nonpolar covalent bond occurs between nonmetals with an electronegativity difference of zero.

Electronegativity

• Electronegativity is the ability of an atom to attract electrons in a chemical bond.
• High electronegativity indicates a greater tendency to attract electrons. Electronegativity can be positive (-atomic number/-metallic character) or negative (+atomic number/+metallic character)

Gas Laws

• Boyle's Law says at constant temperature, the volume of a gas decreases as pressure increases, described as P1V1/T1 = P2V2/T2.
• Charles's Law says at constant pressure, the volume of a gas is directly proportional to its absolute temperature.
• Avogadro's Law says at constant pressure and temperature, the volume of a gas is directly proportional to the number of moles of the gas present.
• Gay-Lussac's Law says at constant volume, the pressure of a gas is directly proportional to its absolute temperature.
• The Ideal Gas Law is given by PV = nRT, with variations to solve for pressure (P), volume (V), and temperature (T).
• Dalton's Law of Partial Pressures The total pressure of a gas mixture equals the sum of the partial pressures of each individual gas in the mixture.
• Real Gas Equation Accounts for non-ideal behavior with the equation P (V-nb) = nRT and the Van der Waals equation
• Various formulas for calculating density (d), molar mass (M), and other gas properties, including the gas constant R = 8.314, molar volume Vmolar = 22.4 L, and Avogadro's number.
• Conversions between Celsius and Fahrenheit (°C = (°F-32) / 1.8, °F = (1.8 x °C) + 32) and Celsius and Kelvin (K = °C + 273.15, °C= K-273.15).
• Standard atmospheric pressure is 1 atm = 760mmHg = 101 325 pa or 101.325KPa.

This material covers the classification of matter into substances, mixtures, elements and compounds, and atoms and molecules. Key concepts include defined composition, distinctive properties, and chemical bonding. It also touches on physical and chemical properties of matter, as well as Dalton's atomic theory.