Chemical Equations Main Concept: A chemical change may be represented by a molecular, ionic, or net ionic equation.

Chemical Equations Chemical Equations Types of Chemical Equations Balanced Molecular Ionic Net Ionic Types of Chemical Reactions

- Chemical equations represent chemical changes - they must contain equal numbers of atoms of every element on each side to be “balanced”

- Depending on context, there are different forms of the balanced chemical equations - Be aware of the different forms: balanced molecular, ionic, or net ionic reaction equation - Know circumstances under which any of them might be the most useful form

Pb2+ (aq) + 2 NO32- (aq) + 2 K+ (aq) + 2 I- (aq)  - Balanced Molecular Equation: - most equations you’ve used Pb(NO3)2 (aq) + 2 KI (aq)  PbI2 (s) + 2 KNO3 (aq) - Ionic Equation (Complete Ionic Equation): - ions dissolved in solutions Pb2+ (aq) + 2 NO32- (aq) + 2 K+ (aq) + 2 I- (aq)  PbI2 (s) + 2 K+ (aq) + 2 NO3- (aq)

Pb2+ (aq) + 2 NO32- (aq) + 2 K+ (aq) + 2 I- (aq)  PbI2 (s) + 2 K+ (aq) + 2 NO3- (aq) - Net Ionic Reaction Equation - like ionic equation, but focusing only on the important ions - often useful for redox reactions Pb2+ (aq) + 2 I- (aq)  PbI2 (s)

Equation Practice

- A balanced equation for a reaction can represent chemistry at any level *** You should be able to translate into a symbolic depiction at the particulate level

Synthesis and Decomposition Reactions Main Concept: Synthesis reactions are those in which atoms and/or molecules combine to form a new compound.  

Synthesis Reactions C + O2  CO2 CaO + H2O  Ca(OH)2 2CO + O2  2CO2

Decomposition Reactions Decomposition is the reverse of synthesis, a process whereby molecules are decomposed, often by the use of heat.

Decomposition Reactions H2CO  H2O + CO2 H2SO3  H2O + SO2 NH4OH  H2O + NH3

Decomposition Reactions 2H2O  2H2 + O2 C12H22O11  12C + 11H2O 2H2O2  2H2O + O2

Single Replacement Reactions Cu + 2AgNO3  2Ag + Cu(NO3)2 Fe + Cu(NO3)2  Fe(NO3)2 + Cu Ca + 2H2O  Ca(OH)2 + H2

Double Replacement Reactions 2KOH + H2SO4  K2SO4 + 2H2O FeS + 2HCl FeCl2 + H2S AgNO3 + NaCl  AgCl + NaNO3

Stoichiometry Main Concept: Quantitative information can be derived from stoichiometric calculations utilizing mole ratios from the balanced chemical equations.  Stoichiometry has real-world applications.

- Coefficients of balanced chemical equations contain information regarding proportionality of amounts of substances involved in reaction - Values can be used in chemical calculations that apply the mole concept - The most important place for this is the laboratory.

With stoichiometry, we can… - Calculate amount of product expected be produced in laboratory experiments - Identify limiting and excess reactant; calculate percent and theoretical yield for a given laboratory experiment.

With stoichiometry, we can… - Investigate gases, particularly with respect to the experimental determination of molar mass of a gas. - Better understand solution chemistry, including titrations.