Introduction to Chemistry: Matter and Properties

• Chemistry is the study of matter, its properties, and how matter changes
• Matter has mass and occupies space

States of Matter

• Solids possess a definite shape and volume
• Liquids have a definite volume but take the shape of their container
• Gases lack a definite shape or volume, expanding to fill available space
• Plasma constitutes an ionized gas

Properties of Matter

• Physical properties can be observed or measured without altering a substance's composition; examples include color, density, and melting point
• Chemical properties describe how a substance transforms into a new one, such as flammability and reactivity
• Intensive properties, like density and temperature, are independent of the amount of substance
• Extensive properties, such as mass and volume, depend on the amount of substance

Chemical Change vs Physical Change

• Physical changes alter the form or appearance of a substance without changing its chemical composition, such as melting or boiling
• Chemical changes result in a change in chemical composition, forming a new substance, like burning or rusting

Mixtures

• Mixtures are combinations of two or more physically combined substances
• Homogeneous mixtures exhibit uniform composition throughout, like saltwater
• Heterogeneous mixtures have non-uniform composition with easily distinguished components, like salad dressing

Pure Substances

• Elements cannot be broken down into simpler substances by chemical means, examples being gold and oxygen
• Compounds consist of two or more elements chemically combined in a fixed ratio, examples being water and salt

Separation Techniques

• Distillation separates liquids based on differing boiling points
• Filtration separates solids from liquids
• Chromatography separates substances based on affinities for stationary and mobile phases
• Evaporation separates a soluble solid from a liquid

Atoms

• Atoms are the fundamental building blocks of matter
• Atoms comprise protons, neutrons, and electrons
• Protons are positively charged particles within the nucleus
• Neutrons are neutral particles located in the nucleus
• Electrons, negatively charged, orbit the nucleus

Atomic Number and Mass Number

• Atomic number (Z) represents the number of protons in an atom, determining the element
• Mass number (A) indicates the total count of protons and neutrons in an atom

Isotopes

• Isotopes are atoms of the same element with varying neutron counts
• Isotopes share the same atomic number but differ in mass numbers

Ions

• Ions are atoms that have either gained or lost electrons
• Cations are positively charged ions (resulting from electron loss)
• Anions are negatively charged ions (resulting from electron gain)

Molecules and Chemical Formulas

• Molecules consist of two or more atoms held together by chemical bonds
• Chemical formulas represent the number and type of atoms in a molecule, such as H2O and CO2

Empirical and Molecular Formulas

• Empirical formula denotes the simplest whole-number ratio of atoms in a compound
• Molecular formula indicates the actual number of atoms of each element in a molecule
• The molecular formula is a multiple of the empirical formula

Chemical Bonds

• Ionic bonds arise from electron transfer between a metal and a nonmetal
• Covalent bonds form through electron sharing between two nonmetals
• Metallic bonds are found in metals, where electrons are delocalized

Naming Compounds

• Ionic compounds (metal + nonmetal) are named by stating the metal and adding "-ide" to the nonmetal; NaCl is sodium chloride
• Covalent compounds use prefixes to denote atom numbers; CO2 is carbon dioxide
• Acids produce H+ ions in solution and follow specific naming rules

The Mole

• The mole (mol) is a unit of amount; 1 mole equals 6.022 x 10^23 entities (Avogadro's number)
• Molar mass represents the mass of one mole of a substance (g/mol)
• Used for conversions between mass and moles

Stoichiometry

• Stoichiometry involves quantitative relationships between reactants and products in chemical reactions
• Balanced chemical equations are crucial for stoichiometric calculations
• Mole ratios are derived from coefficients in a balanced equation

Limiting Reactant and Percent Yield

• The limiting reactant is fully consumed in a reaction, dictating the amount of product formed
• Theoretical yield is the product amount formed based on the limiting reactant
• Actual yield is the product amount obtained in a reaction
• Percent yield is calculated as (Actual yield / Theoretical yield) x 100%

Solutions

• Solutions are homogeneous mixtures of two or more substances
• The solute is the substance being dissolved
• The solvent is the substance doing the dissolving
• Aqueous solutions use water as the solvent

Concentration

• Concentration is the amount of solute in a given amount of solvent or solution
• Molarity (M) is defined as moles of solute per liter of solution (mol/L)
• Molality (m) is defined as moles of solute per kilogram of solvent (mol/kg)

Acids and Bases

• Acids donate protons (H+) in water
• Bases accept protons (H+) in water
• The pH scale measures acidity or basicity (0-14)
• pH < 7 indicates an acidic solution
• pH = 7 indicates a neutral solution
• pH > 7 indicates a basic solution

Oxidation and Reduction

• Oxidation involves the loss of electrons
• Reduction involves the gain of electrons
• Redox reactions involve electron transfer

Organic Chemistry

• Organic chemistry is the study of carbon-containing compounds
• Hydrocarbons consist solely of carbon and hydrogen
• Functional groups are groups of atoms that impart characteristic properties to organic molecules

Explore the fundamental concepts of chemistry, including the definition and states of matter (solid, liquid, gas, plasma). Learn about physical and chemical properties, and differentiate between intensive and extensive properties. Understand the differences between physical and chemical changes.