1. Ions-needed for life!
Dr. Robert D. Craig, Ph.D.
• Experiment on rections of ions with acids and
bases
• Ions effect pH
• Ions effect Diffusion
• Ions effect Homeostasis
• Ions are responsible for nervous system

2. Let’s begin

3. Ions-needed for life
• Ions effect pH
• Ions effect Diffusion
• Ions effect Homeostasis
• Ions are responsible for nervous system

4. Nine essential
• PO4 2- Mg 2+
• OH- Ca 2+
• HCO32- Na+
• Cl- K+ , H+
• Nervous system
• pH
• Ion channel-lipid bilayer
• Fe2+-Hemoglobin

5. .
•
• In Part A, a series of tests for the chemical
properties of known compounds in aqueous
solutions are conducted. A similar series of
tests are conducted on an unknown set of
compounds in Part B.

6. .
• A similar series of tests are conducted on a
unknown set of compounds in Part B. In each
case, an unknown compound is identified

7. For the reaction matrix
• You should discuss and interpret your
observations as follows:

8. Please label everything
• You will carry out 15 chemical reactions
against these reagents
• Sodium Chloride
• Sodium Carbonate
• Magnesium Sulfate
• Ammonium Chloride
• Water

9. Your matrix for reagent one (1)
NaCl(s) Na2CO3(aq) MgSO4(aq) NH4Cl(aq) H2O(l)
AgNO3(aq)

10. terminology
• The report sheet or the “Reaction matix”
• Is designed to help organized Your work
• Because the space is limited –You can use codes
to fill in data:
• “P” – precipitate + color
• “c” – cloudy + color
• “nr”- no reaction
• “g” –gas no odor
• “go” –gas , odor

11. What is the nature of a chemical
reaction>

12. Most reactions take place

13. Scientist describe reactions in terms
of:
• Molecular
• Total Molecular
• Net Ionic: “it is the net ionic that contains the
important players” The rest of the reaction
are “spectators”

14. How do I know a chemical reaction has
taken place????

15. What to look for . . .
• A gas evolved
• A precipitate “solid” appears
• Heat may be evolved or absorbed
• A color change might take place
• A change in odor
• Possibly a “sound”

16. H2S – rotten eggs
• For well over a century, hydrogen sulfide was important in
analytical chemistry, in the qualitative inorganic analysis of
metal ions. In these analyses, heavy metal (and nonmetal)
ions (e.g., Pb(II), Cu(II), Hg(II), As(III)) are precipitated from
solution upon exposure to H2S. The components of the
resulting precipitate redissolve with some selectivity

17. silver chloride (AgCl)
• An example of a precipitation reaction:
Aqueous silver nitrate (AgNO3) is added to a
solution containing potassium chloride (KCl),
the precipitation of a white solid, silver
chloride is observed. (Zumdahl, 2005)
• AgNO3 (aq) + KCl (aq) → AgCl (s) + KNO3 (aq)
• The silver chloride (AgCl) has formed a solid,
which is observed as a precipitate.

18. the ionic equation
• This reaction can be written emphasizing the
dissociated ions in a combined solution. This is
known as the ionic equation.
Ag+ (aq) + NO3− (aq) + K+ (aq) + Cl− (aq) →
AgCl (s) + K+ (aq) + NO3− (aq)

19. (Zumdahl, 2005)
• A final way to represent a precipitate reaction
is known as a net ionic reaction. In this case,
any spectator ions (those that do not
contribute to the reaction) are left out of the
formula completely. This simplifies the above
equations to the following:
• Ag+ (aq) + Cl− (aq) → AgCl (s)
•

20. Oxidation and reduction

21. .
• In addition, the following multistep acid-base
reactions affect the course of rust formation:
• Fe2+ + 2 H2O ⇌ Fe(OH)2 + 2 H+
• Fe3+ + 3 H2O ⇌ Fe(OH)3 + 3 H+

22. Simple dissolution MgOH2

23. Burning Mg(s)
Mg(s) + O2 (g) -> MgO(s) + Heat +
light

24. Heat may be absorbed
• Icy –hot or sprinkling salt on snow

25. Please Turn to figures . . .
• 2.2a and 2.2b

26. 2. Observations sodium hydroxide test
reagent
• 1. label five tubes(fig 2.3)
• 2. set up 24 well plate
• ***Label B1-B5
• 3. Place 5-10 drops of each of the five known
• Solutions
• 4. Deliver the NaOH—check for Gas!!!
• 5. Please be careful!!!!!!

27. 3. Observations with HCl reagent
• 1. label five tubes(fig 2.4)
• 2. set up 24 well plate
• ***Label C1-C5
• 3. Place 5-10 drops of each of the five known
• Solutions
• 4. Deliver the HCl—check for Gas!!!
• 5. Please be careful!!!!!!

28. Part B
• Chemical properties of unknown solutions
• 1. preparation of solutions
• 2. preparation of reagents
• 3. testing the solutions
• 4. Identification of unkwown

29. Last part –environmental testing
• Obtain a sample of soil , add water
• http://bronxriver.org/?pg=content&p=aboutu
s&m1=1