Chapter 7 - Chemical Reactions Flashcards
Combustion Reactions
- a substance reacts w O, emitting heat and forming one or more O-containing compounds
- type of Oxidation-Reduction Rxn
Precipitation Reactions
reactions in aqueous solutions that form a precipitate (a solid) when two aqueous solutions are mixed
Signs of a Chem Rxn
- color change
- emission of light
- formation of solid
- emission/absorptionof heat
- formation of gas
Reactants
substances on the left side of the chem equations
Products
substances on the right side that are often the outcome
Balanced Equation
in which the numbers of each type of atoms on both sides of the equation are equal
-to balance an equation, we insert coefficients in front of the chem formulas
Aqueous Solution
- homogenous mixture of a substance with water
Strong Electrolyte Solutions
-substances that completely dissociate into ionis in solutions are strong electrolytes
Soluble
a compound is soluble in a particular liquid if it dissolves in the liquid
Insoluble
a compound is insoluble if it DOES NOT dissolve in liquid
Solubility Rules
Li, Na, K, NH4, NO3, C2H3O2 - solulable
Cl, Br, I - soluble except w Ag, Hg, or Pb
SO4 - soluble except w Ca, Sr, Ba, or Pb
Insoluble Compounds
OH, S - except w Li, Na, K, NH4, Ca, Sr, Ba
CO3, PO4 except w Li, Na, K, NH4
Soluble Ions w no exceptions (5)
Li, Na, K, NH4, NO3, C2H3O2
Precipitate
a solid that is formed from a reaction
-only insoluble compounds form precipitate
Molecular Equations
completely neutral formulas for every compound in the reaction
Complete Ionic Equations
- shows each reactant and product as their are actually present in solution
ex) Ag+ + NO3- + Na+ + Cl- => AgCl + Na+ + NO3-
Spectator Ions
in complete ionic equations, some of the ions in solution appear unchanged on both sides of the equation
- these spectator ions do not participate in the rxn
- spectator ions can be omitted to simplify the equations - instead of complete, they are net ionic equations
ex) Ag+ + NO3- + Na+ + Cl- => AgCl + Na+ + NO3-
the SPECTATORS are Na and NO3
Net Ionic Equations
equations which only show the species that actually participate in the rxn (unlike complete ionic equations)
ex) COMPLETE IONIC EQUATION: Ag+ + NO3- + Na+ + Cl- => AgCl + Na+ + NO3-
the SPECTATORS Na and NO3 are removed:
NET IONIC EQUATION: Ag+ + Cl- => AgCl
Acid-Base Reaction
aka Neutralization Rxn
- reactions that form water upon mixing of an acid and a base
- the acid’s H combines with the base’s OH to form H2O
ex) HCl +NaOh -> H2O + NaCl
Gas Evolution Reactions
aqueous reactions that form a gas as a product
-The intermediate product H2CO3 is unstable and becomes H2O(aq) + CO2(g)
compounds that undergo Gas Evolution
H2CO3 - CO2(g)
H2SO3 - SO2(g)
NH4OH - NH3(g)
H2S (g)
Oxidation-Reduction Reaction
aka Redox Rxn
- involved the transfer of electrons
- responsible for the rusting of iron, bleaching of hair, and production of electricity in batteries
- oxidation (loss of e) and reduction (gain of e) must occur together
- substance reacts w elemental O
- metal reacts w nonmetal
- one substance transfers e to another substance
ex) rusting of iron:
4Fe(s) + 3O2(g) => 2Fe2O3(s)
Oxidation
the loss of electrons
Reduction
the gain of electrons
Combustion Reaction
a type of EXOTHERMIC (emit heat) Redox Rxn
-the reaction of a substance w O2 to form 1 or more O-containing compounds; often including H2O
4 types of Chem Rxn
1 Precipitation Rxn
2 Acid-Base Rxn
3 Gas Evolution Rxn (many are also an acid/base rxn)
4 Oxidation Rxn (including Combustion Rxn0
4 Types of Reactions
Synthesis/Combination
Decomposition
Single-Displacement
Double-Displacement
A + B ==> AB
synthesis rxn/combo rxn
AB ==> A + B
decomposition rxn
A + BC ==> AC + B
single displacement rxn
AB + CD ==> AD + CB
double displacement
Synthesis/Combination Rxn
simple substances combine to form more complex substances
ex) 2Na + Cl2 => 2NaCl
or
CaO + CO2 => CaCO3
Decomposition Rxn
a complex substance decomposes into simpler substances
ex) 2H2O => 2H + O2
Displacement Rxns
one element displaces another in a compound
ex)
Zn + CuCl2 => ZnCl2 + Cu
Double Displacement Rxn
2 elements or groups of elements in 2 different compounds exchange placed to form 2 NEW compounds
ex)
HCl +NaOH => H2O + NaCl
