Catalyst
1. Balance the following chemical reaction:
C6H12O6 + O2  H2O + CO2
2. Determine the molar mass (formula weight) of
the following compounds:
a. H2SO4
b. Pb(NO3)2
End
Hair Dryer in a Bath Tub
Justify – TPS
• What chemical properties lead to the explosive
reaction of dropping a hair dryer in water?
Lecture 3.1 – Electrolytes and Net
Ionic Equations
Lecture 3.1 – Net Ionic Equations and
Electrolytes
• LT 3.1 – I can identify a compound as being a
strong, weak, or non – electrolyte.
• LT 3.2 – I can translate a chemical reaction into
a net ionic equation that contains only the
ions/molecules that participate in the chemical
reaction.
Electrolytes vs. Nonelectrolytes
• When you dissolve compounds in water, sometimes
they dissociate and sometimes they do not.
• Electrolyte – Any compound that breaks into ions
when in solution and can conduct electricity
• Nonelectrolyte – Any compound that does not form
ions when in solution and cannot conduct electricity.
Ionic Compounds are Electrolytes
• When a ionic compound is dissolved in water, it
breaks apart into positive and negative ions.
• Polar water molecule breaks up the ionic crystal
Covalent Compounds are
Nonelectrolytes
• When a ionic compound is dissolved in water, it
cannot be broken apart.
• Polar water molecule cannot break apart these
compounds because there are no ions
Strong vs. Weak Electrolytes
• Electrolytes can be characterized as being either
strong or week based on the amount they
dissociate.
• Strong Electrolytes – Compounds that
completely dissociate in water.
• Weak Electrolytes – Compounds that almost
dissociate completely in water
Class Example
• Is the following compound an electrolyte or a
nonelectrolyte
• If it is an electrolyte is is strong or weak?
KCl
Table Talk
• Is the following compound an electrolyte or a
nonelectrolyte
• If it is an electrolyte is is strong or weak?
C6H12O6
Net Ionic Equations
• Oftentimes we see chemical equations written as
this:
Pb(NO3)2 (aq) + 2KI (aq)  PbI2 (s) + 2KNO3
Molecular Equation
• The electrolytes that are in aqueous solutions
can be written as their ions:
Pb2+ + 2NO32- + 2K+ +2I-  PbI2+ 2K+ +2NO3Complete Ionic Equation
Net Ionic Equations
• Many of the ions are present on both sides, so
they do not participate in the chemical
reaction and can be canceled out.
Pb2+ + 2NO32- + 2K+ +2I-  PbI2+ 2K+ +2NO3-
Pb2+ (aq) + 2I- (aq)  PbI2 (s)
Class Example
• Write the net ionic equation for the following reaction:
Mg(NO3)2 (aq) + Na2CO3 (aq)  MgCO3 (s) + 2 NaNO3 (aq)
Table Talk
• Write the net ionic equation for the following
reaction:
SrBr2 (aq) + K2SO4 (aq)  SrSO4 (s) + 2 KBr (aq)
Investigate and Check
Exit Ticket
1. Are the following compounds electrolytes or
non-electrolytes? If it is an electrolyte, then is
it strong or weak?
a. KBr
b. CO2
c. CH3COOH (a weak acid)
1. Write the net ionic equation for the following
reaction:
Na2CO3 (aq) + Co(NO3)2 (aq)  2NaNO3 (aq) + CoCO3 (s)
Closing Time
• Read sections 4.1 and 4.2 in textbook
• Complete Homework 3.1 Net Ionic Equations for
class Thursday/Friday
• Lab 5 Pre-Lab due at the start of the next class