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

• Synthesis• Two or more substances combine to

form a more complex substance

A + B ABFe(s) + S(s) FeS(s)

H20(l) + SO3(g) H2SO4(aq)

(acid rain)http://www.natgeoeducationvideo.com/film/1233/acid-rain

http://video.about.com/chemistry/What-Are-Types-of-Chemical-Reactions.htm

Episode 605

Classifying Reactions

• Decomposition• A single substance is broken down

into two or more simpler substances

AB A + BH2O (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 + BZn (s) + 2HCl(aq) ZnCl2(aq) + H2(g)

2Al(s) + 3CuCl2(aq) 2AlCl3(aq) + 3Cu(s) Cu(s) + MgCl2(aq)

Activity Series: an arrangement of elements in the order of their tendency to react

NR (no reaction)

Episode 605

Activity SeriesLithium

PotassiumBariumCalciumSodium

MagnesiumAluminum

ManganeseZinc

ChromiumNickel

TinLead

(Hydrogen)CopperMercurySilverGold

Decr

easi

ng a

ctiv

ity

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 + BX2KI(aq) + Pb(NO3)2(aq) PBI2(s) + KNO3(g)

PrecipitateAn insoluble solidMay 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