A solution is a uniform mixture of a gas, liquid, or solid.

1
CH 103 CONVERSION OF A CARBONATE TO A
CHLORIDE STOICHIOMETRY

• A solution is a uniform mixture of a gas, liquid,
  or solid.
• A solvent is the component of a solution that is
  present in a greatest quantity. It is the 1
  component that determines whether a solution is a
  solid, liquid, or gas.
• Conversely, a solute is a component of a solution
  that is present in a smaller quantity than the
  solvent. Or a solute is a reagent that undergoes
  a change of state when it forms a solution.
• For example, a spoonful of sugar dissolves in a
  cup of boiling water to make a solution.
• What is the solvent?
• What is the solute?

Water
Sugar
2
STOICHIOMETRY

• The phase labels s, l, and g are used to
  identify the solid, liquid, and gaseous states of
  matter, respectively.
• In addition, aq is used to identify a solute in
  the aqueous phase that is, a solute dissolved in
  water.
• H2O(s) is solid water or ice.
• H2O(l) is liquid water.
• H2O(g) is gaseous water or steam.
• K(aq) is potassium ion dissolved in water.

3
STOICHIOMETRY

• To be valid, a chemical reaction must satisfy 3
  conditions.
• First, it must be consistent with experimental
  facts.
• Second, it must conserve mass.
• Third, it must conserve electrical charge.
• 2Ag(aq) S2-(aq) ? Ag2S(s)
• Does an aqueous solution of colorless silver
  ions, Ag(aq), combine with an aqueous solution
  of colorless sulfide ions, S2-(aq), to form the
  black precipitate Ag2S(s)?
• Is mass conserved?
• Is electrical charge conserved?

Yes.
Yes. The reactants have 2 moles of Ag and 1 mole
of S, and the products also have 2 moles of Ag
and 1 mole of S.
Yes. The reactants have 0 net charge, and the
products also have 0 net charge.
4
STOICHIOMETRY

• In the Arrhenius theory an acid produces H in
  aqueous solution and a base produces OH- in
  aqueous solution.
• The more general Brønsted-Lowry theory defines an
  acid as a H donor and a base as a H accepter.
• A salt is the product from the reaction of an
  acid and a base.
• HCl is an ____.
• NaOH is a ____.
• NaCl is a ___.

acid. It produces or donates a H in an aqueous
solution.
base. It produces a OH- an aqueous solution,
which can accept a H from an acid.
salt. It can be produced from an acid and a base
as follows HCl(aq) NaOH(s) ? NaCl(s) H2O(g)
5
TODAYS EXPERIMENT

• The net reaction for todays experiment is
• Na2CO3(s) 2HCl(aq) ? 2NaCl(s) CO2(g)
  H2O(g)
• One mole of solid sodium carbonate (Na2CO3)
  reacts with 2 moles of aqueous hydrochloric acid
  (HCl) to make 2 moles of solid sodium chloride
  (NaCl), 1 mole of gaseous carbon dioxide (CO2),
  and 1 mole of gaseous water (H2O).
• Use this table to confirm that mass is conserved.

Element Moles of Reactant Moles of Product
Na C O H Cl
2
2
1
1
3
3
2
2
2
2
6
TODAYS EXPERIMENT

• Na2CO3(s) 2HCl(aq) ? 2NaCl(s) CO2(g)
  H2O(g)
• What is the theoretical (or maximum) yield of
  NaCl(s) if 0.503 g of Na2CO3(s) reacts with
  excess HCl(aq)?
• First, what does excess HCl(aq) mean?
• HCl(aq) is NOT the limiting reagent and the
  maximum yield of NaCl(s) depends on the initial
  amount of Na2CO3(s).
• What is the percent yield if 0.532 g of NaCl are
  actually produced?

7
AVERAGE DEVIATION AND STANDARD DEVIATION

• Average deviation and standard deviation are
  measures of precision. That is, they are used to
  quantify the agreement between repeated
  measurements of the same sample.

8
AVERAGE DEVIATION AND STANDARD DEVIATION

• Calculate the average and standard deviations for
  the following 3 measurements of the same sample.

9
SAFETY

• Give at least 1 safety concern for the following
  procedures that will be used in todays
  experiment.
• Heating a crucible with a flame.
• Injury from a burn or causing a fire. Be
  careful. Do not wear loose clothing or long
  hair. A crucible can shatter when heating wear
  your goggles at all times.
• Using Na2CO3(s) and concentrated HCl.
• These are irritants. Wear your goggles at all
  times. Immediately clean all spills. If you do
  get either of these in your eye, immediately
  flush with water.
• Generating H2O(g) and HCl(g).
• Again, these are irritants. Wear your goggles at
  all times. Immediately clean all spills. If you
  do get either of these in your eye, immediately
  flush with water.
• Your laboratory manual has an extensive list of
  safety procedures. Read and understand this
  section. Ask your instructor if you ever have
  any questions about safety.

10
SOURCES

• Barnes, D.S., J.A. Chandler. 1982. Chemistry
  111-112 Workbook and Laboratory Manual. Amherst,
  MA University of Massachusetts.
• Petrucci, R.H. 1985. General Chemistry Principles
  and Modern Applications, 4th ed. New York, NY
  Macmillan Publishing Company.
• Spencer, J.N., G.M. Bodner, L.H. Rickard. 2006.
  Chemistry Structure and Dynamics, 3rd ed. New
  York, NY John Wiley Sons, Inc.
• Structure Probe, Inc. 2006. Standards for
  Microanalysis - Silver Sulfide - SPI Supplies. .
  Available http//www.2spi.com/catalog/standards/a
  web/synthet/silver_sulfide.shtml accessed 7
  September 2006.