CHEMICAL REACTIONS
Chemical Reaction – process by which atoms are rearranged to form different substances
Write chemical equations to show reactions
Reactants – starting substances
Products – substances formed from reaction
the symbol -> means yield (used instead of an equal sign) splits equation
into two sides
symbols next to substances also show state of substances
(s) = solid
(l) = liquid
(g) = gas
(aq) = aqueous solution (dissolved in water)
Balancing Chemical Equations
Law of Conservation of Matter – matter cannot be created or destroyed
only changed
Because of this law chemical equation must be balanced
Use coefficients to balance equations
Coefficients – numbers in front of substances
Ex. Balance H2 + O2 -> H2O
(count atoms and make sure each side has same amount)
2H2 + O2 -> 2H2O
Types of Chemical Reaction
Synthesis reaction – two or more substances react to form one substance
Combustion reaction – oxygen combines with a substance to make heat
and energy
Decomposition reaction – single compound breaks apart
Replacement reactions
Single replacement – an atom replaces another A + BX -> AX + B
Single replacements depend on reactivity of substances to
see if they will replace or not
Metal activity series – orders metals by reactivity
Most reactive on top
Double replacement – exchange of ions between compounds
AX + BY -> AY + BX