Chapter 11
Chemical Reactions
11.1 Chemical Reactions
Reactants: starting material in a chemical
reaction
Products: substance formed in a chemical
reaction
→ : arrow means “yields”
11.1 cont
+ : plus sign means “and”, separates
products and reactants
Law of conservation of mass: in any
chemical or physical change, mass is
neither created nor destroyed.
11.1 Writing Chemical Equations
Skeleton equation: a chem. rxn that does
not indicate the relative amounts of the
reactants and products
Chemical Equations: describe what occurs
in a chemical reaction.
Reactants on left ~ arrow ~ Products on right
Catalyst: a substance that speeds up a
chemical reaction w/o being used up.
(written on top of arrow)

11.1 cont.
Symbols used in chemical equations
→ - “yields”
+ - “and”
(s) – solid reactant or product
(l) – liquid reactant or product
(g) – gas reactant or product
(aq) – aqueous solution, reactant or product
→
heat
→
Elec.
→
H2SO4
11.1 Balancing Equations
Balancing Equations: has equal numbers
of the same type of atom on both sides of
the equation
Whole number coefficient: used to balance
equations
11.2 Types of reactions
Combination reaction: two or more
substances react to form a single
substance
Decomposition reaction: single compound
is broken down into two or more products
Rxns cont.
Single-replacement: atoms of one element replace
the atoms of another element in a compound
Double-replacement: involve an exchange of
positive ions between two compounds
Combustion: an element or a compound reacts
with oxygen, often producing energy in the form of
heat and light.
(FIRE!!)
11.3 Reactions in Aqueous
Solutions
Complete ionic equation – shows
dissolved ionic compounds as dissociated
free ions.
Spectator ion – an ion that appears on
both sides of a complete ionic equation
and is not directly involved in the reaction
11.3 cont
Net ionic equation – an equations for a
reaction in solution that shows only those
particles that are directly involved in the
chemical change.