Ionic and Covalent Bonds

To identify the nature of ionic and covalent bonds and determine how ionic and covalent compounds differ.

Research Questions:

• Describe the structure of an atom.
• What is an element?
• What is a compound?
• What contributes to the stability of a compound?
• What is an ion? What is an ionic bond?
• What conditions are needed to allow for ionic bonding?
• How are electrons involved in chemical bonding?
• At what energy levels are electrons shared or transferred?
• Under what conditions does sharing take place?
• Construct a model that explains ionic bonding.  Illustrate bonding between magnesium and oxygen.
• What is an electrolyte?

As for the methodology of this project, this science fair experiment also serves to acquaint students with the essential processes of sciencing such as the importance of the use of a control, of identifying dependent and independent variables, of data collection, of pictorial and or graphic presentation of data and of being able to make better judgments as to the validity and reliability of their findings. They take on the role of scientists and in the process behave as one.

Materials:

• Sugar
• Table salt
• Distilled water
• 2 metric measuring cups
• 2 test tubes
• 2 stirring rods
• Large can of sterno
• Tripod
• Wire gauge
• Matches
• Fire extinguisher
• Bulb
• Bulb holder
• Insulated wire
• Dry cell
• Timer

Do not forget your safety equipment!!!

Experimental Procedure:

1. Gather all the materials you will need for this project which include sugar, table salt, distilled water, 2 metric measuring cups, 2 test tubes, a stirring rod, a test tube holder, 4 small labels, a pen, a large can of sterno, a tripod, a heavy wire gauge, matches, a fire extinguisher, a bulb, a bulb holder, insulated wire, a dry cell and a timer. (A camera if you wish to take photos of the procedure and the results.)
2. Copy the Data Chart provided below so that you can readily record your observations.
3. Label a test tube and a measuring cup sugar and the second test tube and measuring cup salt.
4. Put on those safety glasses, the apron and the gloves. Set up your heating equipment. Set up the tripod, cover the top with the heavy wire gauze and place the open can of sterno on the gauze. Make sure it is stable.
5. Use your measuring cups, put an equal amount of salt and sugar in each cup and then transfer each into the test tube labeled sugar and salt.
6. Record the time, safety glasses on, light the sterno and using the test tube holder heat the salt over the hot sterno.Keep the mouth of the test tube away from you. Watch for the salt to melt. How long did it take for the salt to melt? Record your data in the chart. Now, do the same for the sugar. Remember; keep the mouth of the test tube away from you. Record how long it took for the sugar to melt.
7. Now measure off 50 mL of distilled water with the “ salt” measuring cup. Add two tablespoons of salt to the water and set it aside.
8. Repeat step #8 using 50mL of distilled water with the “sugar” measuring cup. Add two tablespoons ofsugarand set it aside.
9. Take your light bulb holder, screw in the bulb, cut 3 pieces of wire of about 50 cm long. Connect the wires so that you have one wire from the bulb holder attached to the battery terminal, one other wire from the bulb holder will be submerged in the beaker of salt solution and then the sugar solution, Note, one wire from the battery is free to be submerged in each of the solutions, so that we can test each one separately for conductivity. Do you think the sugar solution will conduct the electric current and thereby light the bulb? How about the salt solution? Which is an electrolyte?
10. Observe the conductivity of each solution and record the results.
11. Analyze your data. Why were we concerned with the melting points of sugar and salt? How did this data impact on our results?
12. From your data, which compound is the better conductor of electricity? Which one is ionic? Which one is covalently bonded? How do you know?
13. Distilled water! We uses distilled water! Why? Why not tap water? You may want to research this question.
14. Write up this project. Be certain to include all of your data as well as the bibliography you use to answer the research questions. If you took some photos, include these in your report and in your display.

                                                           Data Chart (to be copied)

Terms/Concepts: Atoms; Protons; Electrons; Neutrons; Ions; Metals; Non metals; Bonding; Ionic bonding; Ionic compounds 

References:

• Masterton,W. Slowinski, E. Walford,E.,Chemistry Holt, Rinehart and Winston, New York, 1980