MODULE

Cards (47)

  • Chemistry
    is the study of matter and the changes it undergoes
  • Matter
    is anything that occupies space and has mass
  • Substance
    is a form of matter that has a definite composition and distinct properties
  • Mixture
    is a combination of two or more substances in which the substances retain their distinct identities
  • Homogeneous mixture
    composition of the mixture is the same throughout eg. soft drink, solder
  • Heterogeneous mixture
    composition is not uniform throughout eg. iron filings in sand Milk
  • Physical means
    can be used to separate a mixture into its pure components
  • Element
    a substance that cannot be separated into simpler substances by chemical means
  • 118 elements have been identified
    82 elements occur naturally on Earth eg. gold, aluminum, lead, oxygen, carbon, sulfur
    36 elements have been created by scientists eg. technetium, americium, seaborgium
  • Compound
    is a substance composed of atoms of two or more elements chemically united in fixed proportions
  • Compounds can only be separated into their pure components (elements) by chemical means
  • Molecule
    is an aggregate of two or more atoms in a definite arrangement held together by chemical forces
  • Diatomic molecule
    contains only two atoms eg H2, N2, O2, Br2, HCl, CO
  • Polyatomic molecule
    contains more than two atoms eg O3, H2O, NH3, CH4
  • Ion
    is an atom, or group of atoms, that has a net positive or negative charge
  • Cation
    Ion with a positive charge
    If a neutral atom loses one or more electrons
    it becomes a cation
  • Anion
    Ion with a negative charge
    If a neutral atom gains one or more electrons
    it becomes an anion
  • Monatomic ion
    contains only one atom eg Na+, Cl- , Ca2+, O2- , Al3+, N3-
  • Polyatomic ion
    contains more than one atom eg. OH- , CN- , NH4 +, NO3 -
  • Ionic compounds
    consist of a combination of cations and an anions
  • Chemical Bonds
    net forces of attraction that hold atoms together
  • Covalent Bond
    sharing of e-
    atoms of non-metals combine
    electronegativity difference is 0 to < 2
  • Electronegativity
    is the ability of an atom to attract toward itself the electrons in a chemical bond
  • Ionic Bond
    attraction between cations and anions
    atoms of metal and nonmetal combine
    metals lose e- (cations), nonmetals gain e- (anions)
  • Valence electrons
    are the outer shell electrons of an atom. The valence electrons are the electrons that participate in chemical bonding
  • Lewis Dot Symbol
    Consists of the symbol of an element and 1 dot for each valence e- in an atom of the element
  • Octet Rule
    Observed tendency of atoms (representative elements) to lose , gain or share e- in order to acquire an octet e- in their outermost main energy level
  • Valence Shell Electron Pair Repulsion Theory (VSEPR)

    Determines the shape of the molecule
  • Polar
    unequal distribution
    different elements
    non-metal
  • Non-polar
    equal distribution
    same elements
    non-metal
  • Intermolecular Forces of Attraction (IMFA)

    Attractive forces between molecules
  • Dipole-dipole forces
    between polar (covalent) molecules
    greater than 0.5 en
    opposite attracts
  • Ion-dipole forces
    attraction between an ion (cation or anion) and a polar molecule
  • London dispersion forces
    Van der Waals interaction
    attractive forces in all (covalent) molecules
  • Ion-ion forces
    Electrostatic forces
    Attractive forces between cations and anions in ionic compounds
  • Hydrogen bond
    special type of dipole-dipole interaction between the H atom in a polar bond and an electronegative O, N or F atom
  • Self-assembly
    The self-organization of components into patterns of structures without human intervention due to different kinds of interactions happening among the components
  • Molecular self-assembly
    involves the Van der Waals interaction, electrostatic, hydrophobic, hydrogen bonds, and coordination bonds
  • Macroscopic objects
    involves gravitational interaction, external electromagnetic field, capillary, and entropic interaction
  • Static self-assembly
    System that are at local equilibrium and do not dissipate energy
    Requires energy to happen