Chemistry- REACTIONS

Sign of Chemical Reaction

-evolution of heat and light
-formation of gas
-formation of precipitate
-color change

precipitate

a solid that forms from mixed solutions. occurs if one of the products is insoluble

Individual atom

"atom"
EX) 2Mg = 2 atoms of magnesium

Covalent atom

"molecule"
EX)3CO2 = 3 molecules of carbon dioxide

Ionic substance

"unit"
EX) 4MgO = 4 units of magnesium oxide

Law of conservation of mass

mass is neither created nor destroyed in a chemical reaction

Combustion

the burning of any substance in O2 to produce heat
A+ O2 = B

CH = hydrocarbon

always produce CO2 and H2O

synthesis

combination of 2 or more substances to form a compound
A+B = AB

Decomposition

a compound breaks down into 2 or more substances
AB = A+B

6 TYPES OF Decomposition

1. metal carbonates decompose = metal oxides and CO2
2. metal hydroxides decompose = metal oxides and H2O
3. metal chlorates decompose = metal chlorides and O2
4. oxyacid's decompose= metals and O2
5. metal oxides decompose= metals and O2
6. water decompose= hydrogen gas and oxygen gas

Single replacement

one element replaces another in a compound
A + BC = AC+ B

in single replacement

FREE element MUST be MORE REACTIVE

double replacement

ions in two compounds "switch partners"
AB+ CD = AD + BC

Precipitate reactions occur when..

aq solutions of ionic compounds are poured together and a solid forms

Solubility rules

happen sequentially

acid/base reactions

one of the products is water

FONCl BrICS

more reactive -- less reactive

balance equation
Al + CuCl2 = Cu + AlCl 3

2 , 3, 3, 2

What type of reaction is
2Al +3CuCl = 3Cu +2AlCl3

single replacement

solubility

the ability of a substance, a solute, to form a solution with another substance, the solvent

insolubility

the inability to form a solution