Bond Types and Physical Properties

Introduction:

The type of bonds present in a compound will determine the general physical properties of that compound. In this experiment the properties of solubility and melting point will be compared for typical ionic and covalent compounds.

Purpose:

The purpose of this laboratory activity is to compare the properties of solubility and melting points for ionic and covalent compounds.

Equipment/Materials:

well plate, 24-hole / sodium chloride
small test tubes / magnesium sulfate
Mel-Temp/capillary tubes / stearic acid
thermometer / vanillin
water / cooking oil
isobutanol

Safety:

·  Always wear safety glasses and an apron in the lab.

·  The Mel-Temp can become very hot. Avoid touching the metal surfaces.

Procedure:

  1. Fill five test tubes 1/3 to 1/2 full of water (very polar). You may use the well plate as a test tube rack.
  2. Fill five test tubes with isobutanol (less polar) to the same level as the water.
  3. Place a sample about the size of half a match head of each of the four solids into separate tubes filled with water. Place a sample of a few drops of cooking oil into the fifth tube.
  4. Place a sample of each solid about the size of half a match head into a separate tube filled with isobutanol. Place a sample of a few drops of cooking oil into the fifth tube.
  5. Mix the contents of the test tubes well. Record your observations regarding the solubility of each of the substances.
  6. Place a sample of each of the solid substances in a melting point capillary tube if you did not already measure its melting point today.
  7. Measure the melting point of the samples, but do not exceed 200oC. Observe for 3 minutes.
  8. Record the melting point as low (below 200oC) or high (above 200oC). Be sure not to exceed the limit of the thermometer.
  9. Identify the type of bonding for each of the solids based upon its formula.
  10. Identify the type of bonding for cooking oil based upon its properties.


Name ______

Partner’s Name(s) ______

Period ______Date______

Bond Types and Physical Properties

Data Table:

Substance / Type of Compound / Solubility
in water / Solubility
in isobutanol / Melting Point
sodium chloride / ______/ ______/ ______/ ______
magnesium sulfate / ______/ ______/ ______/ ______
stearic acid / ______/ ______/ ______/ ______
vanillin / ______/ ______/ ______/ ______
cooking oil / ______/ ______/ ______/ ______

Questions:

  1. What are two general properties of ionic compounds?
  1. What are two general properties of covalent compounds.?
  1. Predict the ranking of these substances from the lowest melting point to the highest

based on your observations.


Bond Types and Physical Properties

ASIM Bond Types and Physical Properties p. 3

Revised 9/06

Group Equipment:

24- well plate to use for test tube rack

10 small test tubes

wooden splints to used as disposable spatulas

Group Materials:

8 Reagent bags are to be shared by 2 groups at each table

Reagent bag contains:

NaCl

MgSO4

stearic acid

vanillin

8 bottles of isobutanol

General Equipment:

MelTemps

Capillary tubes

thermometers

General Materials:

2 bottles of cooking oil to pass around

water

ASIM Bond Types and Physical Properties p. 3

Revised 9/06

ASIM Bond Types and Physical Properties p. 3

Revised 9/06

Solution Preparation Instructions:

100 % isobutanol refill is included in this kit

General Remarks:

Kit is designed to be used by 16 groups of 2 students.

ASIM Bond Types and Physical Properties p. 3

Revised 9/06