SCI Perio

• The Kinetic Molecular Theory - applies only to ideal gases.
• The theory accounts for the physical properties of gases.
• Physical Properties of Gases (expansion)

  • Gases do not have a definite shape
  • Gases do not have a definite volume
  • They expand to take the shape of their container because they are in rapid, random, constant motion.
• (fluidity)

  • Because the attractive forces between gas particles are slight, gas particles glide past one another.
  • They flow just like liquids.
• (Low density)

  • The density of a substance in the gaseous state is about 1/1000 the density of the same substance in the liquid or solid state.
  • That is because their particles are so spread out and far apart from each other.
• Compressibility

  • In compression, gas particles are pressed close together
  • This greatly decreases the volume making transport much easier
• Diffusion - is the mixing of particles of two substances caused by their random motion.
• Effusion - is the process by which gas particles under pressure pass through a tiny opening.
• The difference between solids, liquids, and gases on a molecular level?

  • The energy state of the molecules
  • solids contain the least energy
  • liquids are at a intermediate energy state
  • gases are at the highest energy state
• The Kinetic Molecular Theory of Matter - states that the particles in all matter are in a constant state of motion.
• Ideal Gases - are those that conform perfectly to the postulates of the KMT
• Real Gas - is one that does not conform exactly to the Kinetic Molecular Theory and does not follow the gas laws exactly.
• In real gases the molecules do have volume, In an ideal gas the molecules don't have volume.

  In real gases, the molecules attract each other. In ideal gases the molecules have zero attraction for each other.
• Type of Energy

  • Translational
  • Rotational
  • Vibrational
  • Electronic
• Five Postulates of KMT

  • Constant, Random Motion
  • Temperature measures average KE
  • Molecules have no volume
  • Molecules never attract each other
  • Molecular collisions are elastic
• physical property?


  A characteristics of a substance that can be observed without changing the substance into another substance
• chemical property?


  A characteristics of a substance that describes its ability to change into another substances.
• How can you tell when a chemical reaction occurs?

  Chemical changes occur when bonds break and new bonds form
• How can you tell when a chemical reaction occurs?

  Chemical reactions involve two main kinds of changes that you can observe-formation of new substances and changes in energy
• changes in properties that indicate a chemical change?

  Precipitate - a solid that forms from a solution during a chemical reaction
• changes in properties that indicate a chemical change?

  Color change may indicate a chemical reaction
• Endothermic - A reaction in which energy is absorbed
• Exothermic - A reaction that releases energy in the form of heat
• What does the principle of conservation of mass state?

  • That in chemical reaction, the total mass of the reactants must equal to the total mass of the products
  • Matter is neither created or destroyed
• Open system - matter can enter from or escape to the surroundings
• Closed system - matter is not allowed to enter or leave
• Chemical reactions are associated with chemical change
• whenever a chemical change occurs chemical reaction is said to take place
• chemical reactions are usually irreversible and a new product is formed
• There are five main signs that indicates a chemical reaction has taken place

  • change in color
  • evolution of gas
  • change in temperature
  • change in state
• A word equation describes chemical change using the name of the reactants and products
• According to the law of conservation of mass, total mass must be equal on the both sides of the equation.

  This type of equation is known as a balanced chemical reactions
• What type of chemical reaction is this?

  A + B -> AB

  Answer: Combination Reaction
• What type of chemical reaction is this?

  AB -> A + B

  Answer: Decomposition reaction
• What type of chemical reaction is this?

  A + BC -> AC + B

  Answer: Single displacement reaction
• What type of chemical reaction is this?

  AB + CD -> AD + CB

  Answer: double displacement reaction
• BIOMOLECULES - are molecules of compounds needed for life
• Classifications of biomolecules

  • carbohydrates
  • lipids
  • protein
  • nucleic acid
• Carbohydrates - formally known as saccharides
• Carbohydrates - the major source of energy for the body