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Physical and Chemical Properties of Metals

 

Name:____________________________________________________________Period:_________

 

Prelab

 

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.

 

Procedure

Safety glasses must be worn at all times during this lab.

 

Part I. Physical Properties

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.

 

Part II.  Chemical Properties

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

 

Setup Sheet

 

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

 

Instructor’s Notes

 

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