Ch 2

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  1. Matter
    • anithing that takes up space and has mass
    • can exist as solid, liquid, or gas
    • all matter is composed of chemical elements
  2. Element
    a pure substance that cannot be broken down into other substances
  3. Mass
    • measures the quantity of matter in any given object (wieght)
    • Protons wiegh one atomic mass unit
    • Neutrons weigh one atomic unit
    • eletrons have no mass
  4. Atomic number
    is the number of protons in the nucleus
  5. Isotopes
    Different type of atom of the same chemical element, each having a different number of neutrons
  6. Molecular formula
    • CO2 Tells two pieces of info:
    • Describes which types of atoms are in a molecule and how many of each
  7. Structural formula
    • two-dimentional representations of a given molecule
    • Each line represents one shared pair of electrons
  8. Chemical bondings
    • Covalent bonding: polar and non polar
    • Ionic Bonding:
    • Hydrogen Binding:
  9. Covalent bonds
    • Formed when two atoms share one or more pairs of outer-shell electrons
    • Nonpolar covalent bond: electrons are shared equally, charges are symmetric meaning no difference in electrical charge at one end as opposed to the other.
    • Polar covalent bond: has opposite charges on opposite ends, some atoms have greater electronegativity
  10. Ionic Bond
    • Attraction between oppositely charged ions.
    • Formed when one atom gives up one or more electrons to another atom
    • Ion: an atom that has either a positive or negative charge, due to haveing an unequal number of protons and electrons.
  11. Hydrogen Bonding
    weak attractions between two molecules of water in which a partially positive charged of H atoms is attracted to partially negatively charged Oxygen creating a weak attractions. Water is a polac covalent molecule
  12. Electronegativity
    its a term to measure this kind of pull - When one atom has a greater power to attract electrons to itself than the oter atom
  13. Polarity
    a difference in electrical charge at one end as opposed to the other.
  14. Water as a good solvent
    • Solvent for other polar molecules
    • By dissolving ions and molecules, water allows chemical reactins to occur
    • High speacific heat: the amount of energy required to raise the temprature or a substance by 1 C.
    • It takes longer for water to warm up.
    • Ice floats because solid form of H2O is less dense, formed a maximum number of Hydrogen bonds with each other.
    • Cohesion: tendency of water molecules to stick together. Cohesion give water surface tension
  15. Solution
    mixture of two or more kind of molecules
  16. Solute
    what is being disolved
  17. Solvent
    what disolves other substances
  18. Acids and Bases
    • Whan water dissociates, it releases an equal number of hydrogen ions (H+) and hydroxide ions (OH-)
    • Acids: substances that release hydrogen ions in solution
    • Bases: substances that accept hydrogen ions or yeild hydroxide ioins in solution
  19. pH
    • pH scale: descirbes the acidity of a solution
    • pH stands for "potential hydrogen" or "hydrogen power"
    • The lower the pH, the higher the concentration of H ions
    • THe higher the pH, the lower the concentration of H ions
    • It is a logarithmic scale - pH of 2 is 10 times more acidic than pH of 3 and 100 more acidic than pH 4
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Ch 2
2010-10-13 07:26:28

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