Descriptive Abbreviations
•
•
•
•
(s) Solid
(l) Liquid
(g) Gas
(aq) Aqueous
– dissolved in water
• How do we know the states of matter in a
reaction?
– Word problem tells us
– States of matter from the periodic table
– Common knowledge
Episode 605
Determining State at Room
Temperature
• All metals are solids except for mercury, which
is a liquid.
• Most non-metals are gases with these
exceptions:
– Liquid – bromine
– Solids – carbon, phosphorus, sulfur, selenium,
tellurium, and astatine
• All metalloids are solids
• Ionic compounds are solid, unless told
otherwise.
• Covalent compounds are liquid, unless told
otherwise.
Episode 605
When heated, solid mercury (II)
oxide yields mercury and oxygen gas.
• Write the balanced chemical equation
including the descriptive abbreviations
for the state of matter.
2 HgO(s) → 2 Hg(l) + O2(g)
Episode 605
Classifying Reactions
http://video.about.com/chemistry/What-Are-Types-of-Chemical-Reactions.htm
• Synthesis
• Two or more substances combine to
form a more complex substance
A + B  AB
Fe(s) + S(s)  FeS(s)
H20(l) + SO3(g)  H2SO4(aq)
(acid rain)
http://www.natgeoeducationvideo.com/film/1233/acid-rain
Episode 605
Classifying Reactions
• Decomposition
• A single substance is broken down into
two or more simpler substances
AB  A + B
H2O (l)  H2(g) + O2(g)
2HgO  2Hg(l) + O2↑
Episode 605
Classifying Reactions
• Single Replacement
• A free element replaces a less reactive
element in a compound
A + BY  AY + B
Zn (s) + 2HCl(aq)  ZnCl2(aq) + H2(g)
2Al(s) + 3CuCl2(aq)  2AlCl3(aq) + 3Cu(s)
Cu(s) + MgCl2(aq)  NR (no reaction)
Activity Series: an arrangement of elements
in the order of their tendency to react
Episode 605
Decreasing activity
Activity Series
Lithium
Potassium
Barium
Calcium
Sodium
Magnesium
Aluminum
Manganese
Zinc
Chromium
Nickel
Tin
Lead
(Hydrogen)
Copper
Mercury
Silver
Gold
Episode 605
Classifying Reactions
• Double Replacement
• The elements of a reacting compounds replace
each other
• Normally takes place in an aqueous solution
• Also called metathesis reaction
AX + BY  AY + BX
2KI(aq) + Pb(NO3)2(aq)  PBI2(s) + KNO3(g)
Precipitate
An insoluble solid
May be represented in an equation by (s) or ↓
NaCl(aq) + AgNO3(aq)  NaNO3(aq) + AgCl ↓
Episode 605
Classifying Reactions
• Combustion
• Involves the reaction of a substance
with oxygen
• Often called burning
• The complete combustion of a
hydrocarbon produces CO2 and H2O
CxHy + O2  CO2 + H20
C3H8(g) + 5O2(g)  3CO2(g) + 4H2O(l)
CH4(g) + 2O2(g)  CO2(g) + 2H2O(l)
Episode 605