Chemistry 1-4

• Matter


  Anything that occupies space and has mass
• States of matter


  • Solid
  • Liquid
  • Gas
• Solid


  • Rigid
  • Has a fixed volume and shape
• Solid


  • Ice cube
  • Diamond
  • Iron anvil
• Liquid


  • Has a definite volume
  • Assumes a shape of container
• Gas


  • Air
  • Helium
  • Oxygen
• Three states of water

  • Ice: Solid
  • Water: Liquid
  • Steam: Gas
• Physical properties


  Characteristics of a substance that can be observed or measured without changing the identity of the substance
• Chemical properties


  A substance's ability to form a new substance
• At the atomic level you end up with a different substance than you started with when observing chemical properties
• Categories of matter


  • Pure substances
  • Mixtures
• Element


  The simplest complete chemical substances, each corresponding to a single entry on the periodic table
• All the matter in the world around contains elements
• Mixture


  Two or more pure substances
• Compound


  A substance made from two or more elements, can be broken down into these elements by chemical methods
• Compoundsexamples


  • Water (H2O)
  • Carbon dioxide (CO2)
  • Sugar
• A compound always contains atoms of different elements
• A compound always has the same composition of atoms
• Pure substance


  Always has the same composition
• Pure substances examples


  • Pure water
  • Carbon dioxide
• Homogeneous mixture


  Liquid or solid mixture that has the same proportions of its components throughout a given sample
• Homogeneous mixture examples 


  • Air around you
  • Table salt stirred into water
• Heterogeneous mixture


  Consists of visibly distinguishable parts, contains regions that have different properties from other regions
• Mixtures can be separated based on the physical properties of the components
• Distillation


  Heating or cooling a liquid
• Filtration


  Separates a liquid from a solid
• Chromatography


  Process for separating components of a mixture
• Sublimation


  Conversion of a substance from the solid to the gaseous state without becoming liquid
• Atom


  A particle of matter that defines a chemical element, consisting of a central nucleus surrounded by negatively charged electrons
• Proton


  Positive charge
• Atomic number


  The number of protons in the nucleus, defining the element
• Neutron


  Uncharged particle
• Electron


  Negative charge
• Molecule


  When individual atoms are physically connected together, sharing electrons in a covalent bond
• Compound


  Occurs when elements are combined chemically
• Physical vs chemical changes

  • Sugar fermenting to form ethyl alcohol (chemical)
  • Iron metal melting (physical)
  • Iron combining with oxygen to form rust (iron oxide) (chemical)
• how to find Electrons

  Number of electrons is equal to the proton number
• how to find Neutrons

  Number of neutrons is found by subtracting the atomic number from the atomic mass
• Protons


  Number of protons is equal to the atomic number of the element
• how to find the Mass number

  The total number of protons and neutrons in an atom