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Balancing Equations and Formulas 2014-2015

term / definition or information / examples
chemical equation / w  method of writing what happens in a chemical reaction
w  (g) for gaseous
w  (s) for solids
w  (l) for liquids
w  (aq) solution in water
w  endothermic---absorb heat energy
w  exothermic---release heat energy / 2H2 (g)+ O2 (g) → 2H2O (l) + energy
reactants / w  substances which enter into a reaction
w  before the arrow / Photosynthesis
6CO2 + 6H2O + energy →C6H12O6 + 6O2
reactants---6CO2 + 6H2O
products / w  substances which are formed or created by the reaction
w  after the arrow / Cellular Respiration
C6H12O6 + 6O2 → 6CO2 + 6H2O + energy
products---6CO2 + 6H2O + energy
subscript / w  number that tells how many atoms of an element are in a unit of the compound
w  cannot change subscripts / H2O
2 hydrogen atoms and 1 oxygen atom
coefficient / w  number preceding the compound
w  full size
w  multiplied throughout the formula to which it is attached / 2H2 + O2 → 2H2O + energy
2 in front of 2H2 and 2H2O are coefficients
ratio / places coefficients in order (left to right) using a colon to separate / Photosynthesis
6CO2 + 6H2O + energy →_C6H12O6 + 6O2
Ratio---6:6:1:6
Law of Conservation of Mass
(matter) / w  by Antoine Lavoisier
w  matter cannot be created or destroyed
/ w  start and end with same mass
w  must be balanced
Type of Chemical Reactions / Definition or information / examples
synthesis reaction / ·  two or more simple substances combine to form a more complex substance
·  Two or more reactants yielding one product /
reactant + reactant ® product
A silver spoon tarnishes. The silver reacts with sulfur in the air to make silver sulfide, the black material we call tarnish.
2 Ag + S Ag2S
decomposition reactions / ·  One reactant yields 2 or more products.
·  synthesis and decomposition reactions are opposites.
/
reactant → product + product
Glucose (simple sugar) ferments to ethyl alcohol and carbon dioxide. The sugar in grapes or from grain ferments with yeast to make the alcohol and carbon dioxide. The carbon dioxide is the gas that bubbles out of beer or champagne.
C6H12O6 (glucose) 2C2H5OH (ethyl alcohol) + 2CO2
single replacement reaction
(single displacement) / ·  a single uncombined element replaces another in a compound
·  Two reactants yield two products /
reactant + reactant ® product + product
Silver nitrate solution has a piece of copper placed into it. The solution begins to turn blue and the copper seems to disappear. Instead, a silvery-white material appears.
2 AgNO3 + Cu Cu(NO3)2 + 2 Ag
double replacement reaction
(double displacement) / ·  Parts of two compounds switch places to form two new compounds
·  Two reactants yield two products. /
reactant + reactant → product + product
Hydrochloric acid and sodium hydroxide (acid and base) neutralize each other to make water and a salt.
HCl + NaOH HOH + NaCl
Familiar Name / Chemical Name / Formula
Lye / Sodium hydroxide / NaOH
Milk of Magnesia / Magnesium hydroxide / Mg(OH)2
Ammonia / Ammonia / NH3
Stomach acid or gastric juice / Hydrochloric acid / HCl
Type of sugar (body/carbohydrates) / Glucose / C6H12O6
Marsh gas / Methane / CH4
Carbonic acid gas / Carbon Dioxide / CO2
Nitrogen gas / Nitrogen gas / N2
Oxygen gas / Oxygen gas / O2
Table Salt / Sodium chloride / NaCl
Water / H2O
Ozone / Ozone / O3