Procedure:
1. These reactions will be done as
demonstrations.
A. Copper sulfate pentahydrate decomposes upon
heating. Look at the formula of the
compound being heated. The • 5H2O means that there are 5 waters
of hydration in the compound. This
means that for every one copper sulfate there are five water molecules inside
the crystal. What gas might be given
off? Looking at the test tube, what
evidence do you see for this? When the
test tube is cool, a few drops of water is added to the residue in the test
tube. What happens?
CuSO4 • 5H2O (s)
B.
Potassium chlorate decomposes upon heating. The KClO3 will liquefy and gas bubbles will form. A
wooden splint is lit, the flame is blown out and the glowing splint is quickly
inserted into the mouth of the test tube as the reaction is still
occurring. Then the splint should glow
brightly and burst back into flame.
What gas has been produced?
KClO3(s)
C. Ammonium carbonate decomposes upon heating. As the (NH4)2CO3
is heated, a number of changes can be observed. Look and smell for the products.
What happened to all of the (NH4)2CO3
and what were the products?
(NH4)2CO3(s)
2. Redox reactions: (done by students)
Obtain 1 iron nail, three pieces of copper
foil and one piece of zinc foil. Sand
the bottom of the iron nail until there are some shiny spots. Get five clean test tubes and a test tube
rack. Put one of the five pieces of
metal in each and add 1.0 mL of the indicated solution. Record your observations looking for
evidence of a reaction. Look for
evidence of a reaction as the solutions are added, then set the test tubes
aside and proceed to the rest of the lab.
Recheck these at the end.
Reactions: Observations:
A.
Fe(s) + CuSO4(aq) ®
C.
Cu(s) + AgNO3(aq) ®
D.
Cu(s) + HCl(aq) ®
3. Precipitation reactions:
Obtain 3 clean test tubes. Mix 1.0 mL of each of the indicated
solutions in each and observe the results.
Reactions: Observations:
A. Ba(NO3)2(aq) + Na2SO4(aq) ®
C.
Pb(NO3)2 (aq)
+ K2CrO4 (aq) ®
4. Acid / Base reactions:
Obtain 3 clean test tubes. Mix 1.0 mL of each of the indicated
solutions in each and observe the results.
Reactions: Observations:
A. HCl(aq) +
NaOH(aq) ®
B. Na2CO3
(aq) + HCl(aq) ®
C. NH4Cl(aq) + NaOH(aq)
®
5. Write complete equations for all of the
reactions that occur in parts 1 and 2.
Write NR for no reaction.
Demonstrations:
1A.
1B.
1C.
Redox:
2A.
2B.
2C
2D.
2E.
6. Write the complete molecular equations, complete
ionic equations and net ionic equations for the reactions that occur in parts 3
and 4.
Precipitation:
3A.
3B.
3C.
Acid/base:
4A.
4B.
4C.
7. Reviewing the types of reactions that were done
today, describe a simple test that you could use to determine whether a
solution contains K2SO4(s) or KNO3(s).