Physical and
Chemical Properties of Metals
Name:____________________________________________________________Period:_________
1.
Define
the following terms:
a. Malleability b.
Density c. Specific
heat
2.
Explain
why malleability is an important property when making jewelry out of metal.
3.
You
have decided to make a solid spherical charm for a bracelet. The charm must have a volume of 5.00 cm3. You can make the charm from metal X, which
has a density of 19.32 g/cm3, or form metal Y, which has a density
of 10.49 g/cm3. Which metal
will you use to make the charm, stating reasons for your choice? Calculate the mass of your charm. (Show calculations).
4.
You
have been selected to design a symbolic metallic sign for the opening ceremonies
of the 2010 Olympic games. The sign is
to be carried bare-handed by two individuals.
It is predicted that the sign will be exposed to a fair amount of heat. You must make the sign out of either metal A
or metal B. The densities of both
metals are comparably equal. However,
the specific heat of metal A is 0.443 J/goC and the specific heat of
metal B is 0.136 J/goC. Which metal will you use to make the sign,
stating reasons for your choice?
Physical and
Chemical Properties of Metals
We are in a midst of a frenzied
jewelry-wearing revolution! The old
rules for wearing jewelry are changing overnight. Men wear jewelry as conspicuously as women do. Baseball players as well as other athletes
wear jewelry. Jewelry is worn by men
and women on all occasions and at any time day or night.
In this lab activity, you will investigate the physical and
chemical properties of various metals.
Based on the data you collect, you will look for regularities in the
physical and chemical properties of the metals as related to each metal's
position on the Periodic Table. You
will also evaluate the data you collect to predict which metals would be best
for making jewelry.
Safety glasses must be worn
at all times during this lab.
1.
Remove
contaminates from the surface of each metal by polishing with emery cloth or
steel wool.
2.
Observe
and record the color of each metal.
3.
Place
a sample of each metal on the surface of a brick or a metal plate. Hammer each metal with a wooden mallet.
4.
Record
the relative malleability of the metal in Data Table 1.
5.
Using
your textbook or any other reference book, look up the density, melting point
and specific heat for each metal.
6.
Record
this information in the Data Table 1.
The 3.0M HCl and 3.0M HNO3
must be handled carefully. Clean up any spills immediately. Wash your hands
immediately if you get either reagent on them.
1.
Place
a sample of each metal into separate wells of a plastic 24-well plate. To each metal in a well, add about 20 drops
of 3.0 M HCl.
2.
Record
observations of these reactions in Data Table 1.
3.
Repeat
steps 3 & 4 for each metal, replacing the HCl with 3.0 M HNO3.
This should be done in a hood or a place where there is plenty of ventilation.
4.
Record
observations of these reactions in Data Table 1.
5.
Rinse
the plates with water and dispose of the metals according to your instructor’s
directions.
This experiment is modified from Activity 6.1, The Physical
and Chemical Properties of Metals from Art
in Chemistry; Chemistry inArt,by Greenberg and Patterson, Teacher Ideas
Press, 1998, pp 147-150.
Physical and
Chemical Properties of Metals
Name:
_____________________________________________________________Period: _________
Lab Partner _________________________________________________________Course:_________
Data Table 1
|
Metal |
Color |
Malleability |
Density |
Melting Point |
Specific Heat |
Reaction with HCl |
Reaction with HNO3 |
|
Cu |
|
|
|
|
|
|
|
|
Sn |
|
|
|
|
|
|
|
|
Pb |
|
|
|
|
|
|
|
|
Al |
|
|
|
|
|
|
|
|
Mg |
|
|
|
|
|
|
|
|
Ca |
|
|
|
|
|
|
|
|
Zn |
|
|
|
|
|
|
|
|
Fe |
|
|
|
|
|
|
|
Additional
Observations:
Conclusion Questions
1.
What
is the trend in malleability of Group 2 metals (Mg and Ca) as you go down the
column on the Periodic Table?
2.
What
is the trend in malleability of p-block metals (Al, Sn, and Pb) as you go down
the Period Table?
3.
What
is the trend in malleability of d-block or transition metals (Fe, Cu, and Zn)
as you go across a row on the Periodic Table?
4.
Are
the results of the reactions of the metals with HCl consistent with the
position of the metals on the activity series? Explain your answer by
discussing the individual metals.
5.
Are
the results of the reactions of the metals with HNO3 consistent with
the position of the metals relative to the reduction of NO3-1
on the table of standard reduction potentials? Explain your answer by
discussing the individual metals.
6.
What
level of malleability of a metal would be more suitable for making jewelry?
Explain your answer.
7.
What
level of reactivity of a metal would be more suitable for making jewelry?
Explain your answer.
8.
Which
metal(s) seem to be the most practical for making jewelry from the viewpoint of
malleability and reactivity? Explain your choices?
Physical and Chemical
Properties of Metals
10 24 well plastic plates
10 Small steel plates (about 4in x 4in) The
solid cover plates from electrical boxes work well.
10 Steel hammers
10 Boxes of Kim wipes
10 Distilled water bottles
10 Dropping bottles labeled: 3M HCl
10 Dropping bottles labeled: 3M HNO3
10 Wooden blocks to hold the scintillation
vials
10 Sets of scintillation vials labeled: Cu,
Sn, Pb, Al, Mg, Ca, Zn, Fe
1 Test tube rack 18x150mm with test
tubes labeled: Cu, Sn, Pb, Al, Mg, Ca, Zn, Fe
Steel
wool or sand paper to polish the metals
To
be prepared by the instructor:
3.0M
HCl Add 50mL of conc. HCl to 100mL
of water and dilute to 200mL. Mix.
3.0M
HNO3 Add 38mL of conc. HNO3
to 100mL of water and dilute to 200mL. Mix.
Supply
of
Copper
shot short pieces of 12 or 14 ga copper wire
Tin
pieces
Lead
shot
Aluminum
wire
Magnesium
turnings
Calcium
turnings
Zinc
shot or mossy zinc
Iron
wire or small iron nails or small iron brads
Physical and
Chemical Properties of Metals
1.
The reactions with HNO3 should be done in an exhaust hood or with
plenty of ventilation because toxic NO2 gas will be released by the
more reactive metals. The HCl and HNO3 should be handled carefully
and any spills should be cleaned up immediately.
2.
Some of the metals like lead and tin may melt if they are heated for too long a
period in the burner.
3.
Using a metal plate would allow the use of regular hammers to test the
malleability.
4.
It would save time if the metal were already polished.
5.
You may want to react Ca with water and Mg with HNO3 as a
demonstration to show their high reactivity. You might want to set up a series
of test tubes to show the reaction of the metals with water. The test tubes
could be allowed to stand for awhile to show what happens over a long period of
time.
6.
You may want to demonstrate the reaction of the metals with oxygen and their
relative melting point. Using tongs, hold a sample of each metal in the flame
of a Bunsen burner for about one minute. Observe the color of each metal after
it is removed from the flame and allowed to cool to room temperature. Remove
the metal from the flame if it starts to melt. Protect the bench top with some
wood and heavy aluminum foil. The lead, tin, aluminum, and zinc will melt in
the burner flame. The magnesium and calcium will catch fire in the flame.
7.
The solid cover plates that are used to cover metal electrical boxes are
available at hardware stores work well for testing malleability.
Answers to Conclusion
Questions:
1.
What
is the trend in malleability of Group 2 metals (Mg and Ca) as you go down the
column on the Periodic Table?
Group
2 metals become harder as you go down the column. Group 1 metals become softer.
2.
What
is the trend in malleability of p-block metals (Al, Sn, and Pb) as you go down
the Period Table?
These
metals become softer as you go down the Periodic Table.
3.
What
is the trend in malleability of d-block or transition metals (Fe, Cu, and Zn)
as you go across a row on the Periodic Table?
Transition
metals get harder as you go to the middle of the block and get softer as you
get to the end of the block.
4.
Are
the results of the reactions of the metals with HCl consistent with the
position of the metals on the activity series? Explain your answer by
discussing the individual metals.
All
the metal except copper should react with HCl since they are above hydrogen on
the activity series and should displace hydrogen to form hydrogen gas. Copper
is below hydrogen on the series and should not react.
All
the metals except copper should react with HCl since their reduction potentials
are more negative than the reduction potential of the H+1. The H+1
ion should oxidize the metal to the metal ion while the H+1 ion is
reduced to H2. The reduction of Cu+2 is more positive
than the H+1 ion so H+1 should not be able to oxidize Cu
metal.
5.
Are
the results of the reactions of the metals with HNO3 consistent with
the position of the metals relative to the reduction of NO3-1
on the table of standard reduction potentials? Explain your answer by
discussing the individual metals.
All
the metals should react with HNO3 since their reduction potentials
are more negative than the reduction potential of the NO3-1.
The NO3-1 ion should oxidize the metal in acidic solution
to the metal ion while the
NO3-1
ion is reduced to NO or NO2. The reduction of NO3-1
happens in preference to reducing the H+1 ion.
6.
What
level of malleability of a metal would be more suitable for making jewelry?
Explain your answer.
A
metal of intermediate malleability is desired. If it is too soft, it will not
stand up to wear well. If it is too hard, it will be difficult to shape.
7.
What
level of reactivity of a metal would be more suitable for making jewelry?
Explain your answer.
A
metal with low reactivity is desired so the metal will not react with water and
common acids like vinegar.
8.
Which
metal(s) seem to be the most practical for making jewelry from the viewpoint of
malleability and reactivity? Explain your choices?
Copper
would be a good metal since is fairly malleable and does not react rapidly with
water and normal acids. None of the metal will withstand a strong oxidizing
agent such as nitric acid. Tin, zinc and aluminum react well with acids, which
is a disadvantage, but they are malleable and react only slowly with water. Tin
and lead are too soft. Calcium is too hard and brittle. Calcium and magnesium
are too reactive with water and acids. Iron is hard and too reactive with
water.
Sample
Data and Literature Data:
Data Table 1
|
Metal |
Color |
Malleability |
Density |
Melting Point |
Specific Heat |
Reaction with HCl |
Reaction with HNO3 |
|
Cu |
Red-orange |
Moderate |
8.96
g/cm3 |
1084
oC |
0.385
J/goC |
No
reaction |
Moderate
reaction |
|
Sn |
Silver |
Soft |
7.31
g/cm3 |
232
oC |
0.228
J/goC |
Slow
reaction |
Fast
reaction |
|
Pb |
Silver |
Soft |
11.35
g/cm3 |
334
oC |
0.129
J/goC |
Slow
reaction |
Moderate
reaction |
|
Al |
Silver |
Moderate |
2.70
g/cm3 |
661
oC |
0.90
J/goC |
Fast
Reaction |
Fast
reaction |
|
Mg |
Silver |
Moderate |
1.74
g/cm3 |
649
oC |
1.02
J/goC |
Fast
Reaction |
|
|
Ca |
Silver |
Hard |
1.55
g/cm3 |
839
oC |
0.647
J/goC |
|
|
|
Zn |
Silver |
Moderate |
7.13
g/cm3 |
420
oC |
0.388
J/goC |
Fast
Reaction |
Fast
reaction |
|
Fe |
Silver |
Hard |
7.87 g/cm3 |
1535
oC |
0.449
J/goC |
Slow
reaction |
Moderate
reaction |