Flashcards in Unit 4 Key Terms and Concepts Deck (42)
an atom, a molecule, an ion, or a
combination of cations and anions that gives a
balance of charges. Anything represented by a
a Chemical Equation
uses chemical symbols to
represent what happens in a chemical reaction.
aqueous (dissolved in water) state
indicate how many of the chemical units participate in the reactions
balanced chemical equation
has the same number of atoms of each kind on both sides of the reaction
Law of Conservation of Matter
matter is not
created or destroyed in chemical reactions. Mass
of products = mass of reactants.
one substance splits into two or more simpler substances
a reaction of a substance
with O2 that produce heat and light and oxide products. (CO2 and H2O)
1.6605387 x 10−24 g
Average atomic mass (atomic weight)
the weighted average mass of naturally occurring
isotopes in a sample expressed in amu’s.
Formula mass (formula weight)
the sum of the average atomic masses (atomic weights) of all the atoms in a formula unit. The mass of a compound in amu’s
is the percentage of each element in a compound by mass.
percent composition equation
% element A = mass from element A/(total compound mass) x 100
6.022 x 1023 formula units
an amount of substance containing
the same number of formula units as there are
atoms in 12.000 g of ^12C.
the mass in grams of one mole of a
substance. Numerically equal to formula weight.
The formula mass of water
2(1.008) + 16.00 = 18.02 amu
The molar mass of water
2(1.008) + 16.00 = 18.02 g/mol
The mole is the SI unit for
an amount of substance
The actual numbers of atoms or moles of each element in a compound
a chemical formula that gives the smalles whole number ratios of atoms or moles of each element in a compound
How do you find the empirical formula from a moleuclar formula?
Reduce the subscripts as much as possible.
ex: C6H12O6= CH2O
C6H6 Empirical Formula
Na2SO4 Empirical Formula