by yeixys

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procedure for writting formulas for ionic compounds
  • write the symbol for the metal cations and its charged followed by the sumbols for the nonmetal anion and its charge.
  • adjust the subscript on each cation and anion to balance the equation
  • chech that the sum of the charges for the cations equals the sum of the anions
conversion factors for length
1 kilometer (km)= 0.6214 miles
1 meter (m)= 39.37 inches
1 foot (ft)= 30.48 cm
1 inch (in)= 2.54 cm
conversion factors for mass
1 kilogram (Kg)= 2.205 lb
1 pound (lb)= 453.59 grams (g)
1 ounze (oz)= 28.35 grams (g)
conversion factors for volume
1 liter (L)= 1000 mL= 1000cm3
1 liter (L)= 1.057 qt
1 U.S gal.= 3.785 (L)
1 liter= 1dm3
  • Sr→Stontium
  • Sc→Scandium
    Pt→ Platinum
    Cd→ Cadnium
    Ti→ Thallium
    W→ Tungsten
    Bi→ Bismuth
Density= mass/volume
Mass= (Density)(volume)
volume= mass/Density
water is 1.00 g/cm3  
The sutyd of matter and the changes it undergoes
a consise verbal or mathamatical statement of a relation that is alway the same under the same conditions
Hypothesis: a tentative explanation or prediction of experimental observations
Theory: a principal that explains laws. theories explain why things happen. theories can never be proven ABSOLUTELY true.
Qualitative- non numerical observations such as physical appearance. also whether or not something is there
Quantitative- numerical data, how much of something is there, melting point...etc
Extensive properties depend on the amount of matter present (volume, mass)
Intensive properties independent of the amount of sample present. example would be melting temp. color and density...
Atom- the smallest particle of an element that has the properties of that element
Molecule- tow or more atoms combined in definite ratios
Elements- the simplest substance that is made up of only one type of atom.
Diatomic elements are the halogens
F2, Br2, Cl2, O2, N2, I2, P4, S8
Group 1A-Alkali metals
Group 2A-Alkaline earth metals
Group 7A- Halogens
Group 8A- Nobel gases
law of mass conservation- mass is neither created nor destroyed
law of definite porportions- different samples of a pure chemical substance aslways contain the same proportion of elements by mass
law of multiple porportions- if two elements combnine in different ways to form differnet substance the mass ratios are small, whole number multiples of each other.
atomic number is (Z)=# of protons in nucleus
mass number is (A)= sum of the number of p+n
if the atom has no charge then the number of protons equals the number of electrons
protons are equal to the electrons so if there are 80p there are 80e
Decantation is a process for the separation of mixtures
Precipitation is the formation of a solid in a solution or inside another solid during a chemical reaction or by diffusion in a solid. When the reaction occurs in a liquid, the solid formed is called the precipitate, and the liquid remaining above the solid is called the supernate.
compounds- combination of two or more elements in specified ratios
the chemical molecular formula  gives: -# of atoms of each type in one molecule -# of moles of each element in one mole of the compound ex. DDT C14H9 is a chemical formula.

the empirical formula give:
- relative number iof atoms of each type
-C6H12O6 is the chemical(molecular formula but CH2O is the empirical formula
Molecular composition
  1. #atoms/molecule (molecular formula)
  2. element mass/ mole
  3. weight % =mass of element/mass of molecule)x100
empirical formula- expresses the ratios of atoms in a molcule with the smallest numbers possibe

  1. calculate in 4 steps:
  2. assume 100 g and determine the amount of each element in grams
  3. divide each elemental mass by the corresponding atomic weigh this will give you moles of each element
  4. divide each mole quantity by the smallest mole quantities
  5. multiple each mole quantity by the correct factor
molecular formula- expresses the true number of each atom present
    x of y cards