Genchem

• The state of matter of a substance is attributed to the distance between the particles which make the substance.

  Pressure
• 2 Types Forces of Attraction

  1. Intramolecular Forces
  2. Intermolecular Forces
• Intramolecular Forces

  – forces that happen in a single molecule, they operate between atoms binding them to hold the molecules together
• Intermolecular forces

  The attractive forces between neighboring particles (including molecules, atoms and ions)

  This is what governs all the physical properties of liquid and solid matter

  (boiling point, melting point, viscosity, surface tension etc)
• Van der Waals Forces are weak intermolecular forces

  • The forces are due to the attractions between the partial positive and partial negative electrical charges between molecules
  • These forces are affected by the distance between the molecules (like how when you bring magnets closer together, the attraction is greater)
  • Quickly vanishes at longer distances between interacting molecules.
• Intermolecular forces are the forces that hold molecules in a substance
• Intermolecular forces are the forces that hold atoms in a molecule
• Intermolecular forces are weaker
• intermolecular forces determine the state of matter and their physical properties
• intramolecular forces determine chemical behavior of a substance
• intermolecular forces are attractive forces
• intramolecular forces are chemical bonds
• Types of intermolecular forces

  1. Dipole dipole interaction
  2. London dispersion forces
  3. dipole induced dipole interaction
  4. ion induced dipole interaction
  5. ion dipole interaction
  6. hydrogen bonding
• Hydrogen bonding is the strongest van der waals force
• Dipole dipole interaction

  -attraction that exist between 2 polar molecules
• the more polar the molecule the higher the boiling point
• polar means electronegativity difference
• polar covalent bond 0.5 - 1.9

  Non - polar covalent bond 0-0.4

  Ionic bond 2.4-4.0
• London dispersion forces

  • exist in both polar and non polar molecules via equal sharing of electrons
• • Exist between all species (London dispersion forces)
• Factors Affecting London Forces

  • Increases with increased molecular weight
  • Heavier atoms or molecules have more electrons, and stronger London forces

  (more electrons easier to polarize)
• Dipole induced dipole interaction

  • attraction that exist between Polar molecules and NON Polar molecule.
• Dipole induced dipole interaction

  • between neutral forces
  • Electrons of non polar molecule will be distributed to one side allowing the other side to be positive (distorted) forming an induced dipole
• Ion dipole attraction

  • intermolecular force of attraction between a charge ion (cation or anion) and a molecule.
  • It is found commonly in the solution were ionic compounds dissolve in polar solvents.
• Ion induced dipole attraction

  • An ion-induced dipole attraction is a weak attraction that results when the approach of an ion induces a dipole in an atom or in a non-polar molecule by disturbing the arrangement of electrons in the non-polar species
• Hydrogen Bonding

  • Strongest van der waals forces
  • a special type of dipole-dipole interaction between a highly electronegative atom like oxygen, nitrogen or fluorine and a hydrogen atom.
  • For a hydrogen bond to occur there must be both a
  • The donor in a hydrogen bond is the atom to which the hydrogen atom participating in the hydrogen bond is covalently bonded, usually, a strongly electronegative atom such as N, O, or F
• Deoxyribonucleic Acid or DNA is a chemical compound that stores all the genetic information of a living being. Hydrogen bonding is responsible for the existence of a DNA molecule.

  A strong force of interaction existing between the four parts, namely adenine, guanine, cytosine, and thymine that leads to the formation of DNA
• Proteins are long chain polymers made up of amino acids. These long chains are known as polypeptides.

  They play a key role in the life of all living beings. The primary structure of proteins is formed by the covalent bond existing between the amino acid molecules.

  The secondary structure is made up of the hydrogen bonding present between the different sections of the protein chain
• Detergent and Soap

  Detergent and soap are similar chemically, except for the oil in them. Many soaps use natural fats while detergents use refined petroleum.

  Soap and detergent molecules have two ends which act as a bridge between water molecules and grease (fat) molecules.

  -This allows the soap or detergent to grab onto the grease from a dirty dish and use the other end of the detergent molecule to latch on to water to be washed away.
• the strength of attractions between particles can greatly affect the properties of a substance or solution