Biochem

• What are chemical compounds formed by?

  Joining of atoms
• When is a molecule considered stable?

  When combination energy is lower than atoms' energy
• What are the types of chemical bonds mentioned?

  • Covalent
  • Ionic
  • Hydrogen
  • Dipole-Dipole
  • Dispersion
  • Van der Waals
  • Metallic
• What is a covalent bond?

  Sharing of valence electrons between atoms
• What is the length of a C-C covalent bond?

  1.54 Å
• Why does a covalent bond require a lot of energy to break?

  It contains a lot of energy in a small bond
• What is the reaction for hydrogen forming a covalent bond?

  1. + H → H:H
• What is the reaction for hydrogen and chlorine forming a covalent bond?

  1. + :Cl: → H:Cl:
• What happens in ionic bonds?

  One electron is displaced to another atom
• What results from the displacement of an electron in ionic bonds?

  An imbalance of charge attracting each other
• Between which types of atoms do ionic bonds occur?

  Metal cations and non-metal anions
• What is the reaction for sodium and chlorine forming an ionic bond?

  Na + Cl: → Na⁺ + Cl⁻
• What is the reaction for calcium and chlorine forming ionic bonds?

  Ca + Cl: + Cl: → Ca²⁺ + Cl⁻ + Cl⁻
• What is the reaction for magnesium and oxygen forming ionic bonds?

  Mg + O: → Mg²⁺ + O²⁻
• What are metallic bonds known for?

  Allowing heat and electricity to pass easily
• What is the degree of freedom of electrons in metallic bonds?

  Electrons have freedom in all directions
• What is a hydrogen bond?

  Attraction between H and electronegative atoms
• Which atoms must be involved in hydrogen bonds?

  O, N, or F
• What type of force is a hydrogen bond classified as?

  Intermolecular force
• What are dipole-dipole forces?

  Attractions between polar molecules
• What causes a dipole moment in molecules?

  Unequal distribution of charge
• What is the strength range of dipole-dipole forces?

  5 kJ to 20 kJ per mole
• Why do dipole-dipole forces have a significant effect only when molecules are close together?

  They are much weaker than ionic or covalent bonds
• What characterizes polar molecules?

  Partial negative and positive ends
• In an ICl molecule, which atom bears the partial negative charge?

  Chlorine atom
• In an ICl molecule, which atom bears the partial positive charge?

  Iodine atom
• What is Coulomb's law?

  • Electrostatic force of attraction magnitude
  • Proportional to joining molecules' charge
  • Inversely proportional to distance squared
  • Formula: E = Kq1q2/D²
• What does E represent in Coulomb's law?

  Energy
• What do q1 and q2 represent in Coulomb's law?

  Charge points from two molecules
• What does D represent in Coulomb's law?

  Distance between charge points
• What does K represent in Coulomb's law?

  Proportionality constant
• How are q1 and q2 related in Coulomb's law?

  They are proportional to each other