genchem

• Matter


  Anything that has mass and occupies space
• Classification of matter


  • Elements
  • Compounds
  • Mixtures (homogeneous and heterogeneous)
  • States of matter (solid, liquid, gas, plasma)
• Elements


  Pure substances made of only one type of atom
• Compounds


  Substances composed of two or more elements chemically combined in fixed ratios
• Homogeneous mixtures


  Uniform composition throughout
• Heterogeneous mixtures


  Non-uniform composition with distinct phases
• Solid


  • Definite shape and volume, particles closely packed and vibrate in fixed positions
• Liquid


  • Definite volume but takes the shape of its container, particles are close but can move around
• Gas


  • No definite shape or volume, particles are far apart and move freely
• Plasma


  • Ionized gas with freely moving electrons and ions, found in stars and lightning
• SI Units (International System of Units)


  Standardized units used worldwide for consistency in scientific measurements
• Conversions


  Multiplying or dividing by conversion factors to change units
• Precision


  Measure of reproducibility or repeatability of a measurement
• Accuracy


  Measure of how close a measurement is to the true or accepted value
• Precision ensures consistency and reliability in experimental results
• Accuracy ensures that measurements are close to the true values, minimizing errors in scientific investigations
• Atom


  Basic unit of matter composed of protons, neutrons, and electrons
• Periodic Table


  Organized arrangement of elements based on atomic number and chemical properties
• Ionic Bonding


  Transfer of electrons between atoms, resulting in ions held together by electrostatic forces
• Covalent Bonding


  Sharing of electrons between atoms to achieve a stable electron configuration
• Metallic Bonding


  Electrons are delocalized among metal atoms, creating a "sea" of electrons that holds the metal together
• Synthesis


  Combination of reactants to form a single product
• Decomposition


  Breakdown of a compound into simpler substances
• Single Replacement


  One element replaces another in a compound
• Double Replacement


  Exchange of ions between two compounds
• Combustion


  Reaction with oxygen producing heat and often light
• Balancing Chemical Equations


  Ensuring the conservation of mass by adjusting coefficients to balance the number of atoms on both sides of the equation
• Stoichiometry


  Calculation of quantities of reactants and products in chemical reactions based on balanced equations
• Mole Concept


  Avogadro's number relates moles to number of particles (atoms, molecules, ions)
• Endothermic


  Absorbs heat energy from the surroundings
• Exothermic


  Releases heat energy to the surroundings
• Enthalpy (ΔH)


  Heat content of a system at constant pressure
• Heat Capacity


  Amount of heat required to raise the temperature of a substance by 1 degree Celsius
• Calorimetry


  Measurement of heat exchange in chemical reactions or physical changes using calorimeters
• Hess's Law


  Total enthalpy change of a reaction is independent of the pathway taken
• Standard Enthalpies of Formation (ΔH°f)

  Enthalpy change when one mole of a compound forms from its elements in their standard states
• Quantum Mechanical Model of the Atom

  Describes electrons as wave-like particles in orbitals around the nucleus
• Electron Configurations and Orbital Diagrams

  Arrangement of electrons in energy levels and sublevels within an atom
• Periodic Trends in Atomic Properties

  • Patterns in atomic size, ionization energy, electron affinity, and electronegativity across periods and down groups in the periodic table
• Conversion Factors


  Ratios used to convert from one unit to another