The physical properties of a substance such as melting point, solubility and con
ID: 783009 • Letter: T
Question
The physical properties of a substance such as melting point, solubility and conductivity tell us a lot about the type of bond in a compound. In this experiment, tests on these properties will be performed enabling the classification of compound bonds as ionic or covalent.
Now what do you do?
Introduction:
Objective: To learn the properties of ionic and covalent bonds
Chemical compounds are combinations of atoms held together by chemical bonds. These chemical bonds are of two basic types %u2013 ionic and covalent. Ionic bonds result when one or more electrons from one atom of group of atoms are transferred to another atom. Positive and negative ions are created through this process. In covalent compounds the bonded atoms share the electrons.
The curls and waves in your hair are the result of the many hydrogen, ionic and covalent bonds between the chains of atoms that make up each hair follicle. Styling hair by wetting it or heating it with a curling iron is an attempt to change the hydrogen and ionic bonds so that they will form a new shape. The changes are temporary, and as soon as you wash your hair, the hairstyle is gone. The solutions in a %u201Cpermanent%u201D, however, break and reform covalent bonds. This is why a %u201Cpermanent%u201D does not wash out when you wash your hair.
The physical properties of a substance such as melting point, solubility and conductivity tell us a lot about the type of bond in a compound. In this experiment, tests on these properties will be performed enabling the classification of compound bonds as ionic or covalent.
Procedures:
Part A %u2013 Melting Point
1. Obtain six watch glasses. Place a two-gram sample of the following compounds in a separate watch glass:
Watch Glass #1 : 2g of Calcium Chloride
Watch Glass #2 : 2g of Citric Acid
Watch Glass #3 : 2g of Phenyl Salicylate
Watch Glass #4 : 2g of Potassium Iodide
Watch Glass #5 : 2g of Sodium Chloride
Watch Glass #6 : 2g of Sucrose
2. Under each watch glass place a Bunsen burner.
3. In the chart provided in the observations section, record the order of melting (i.e. 1st, 2nd, etc). If the compound does not melted after 2 minutes put %u201Cno%u201D in the table.
4. Clean the lab workspace.
Part B %u2013 Solubility in Ethanol
1. Obtain six test tubes and add 25ml of ethanol to each test tube.
2. Add a two-gram sample of each of the above compounds to each test tube.
3. Stir the samples.
4. In the chart provided record if each compound is solubility in ethanol.
5. Clean the lab workspace.
Part C %u2013 Solubility in Water
1. Obtain six test tubes and add 25ml of water to each test tube.
2. Add a two-gram sample of each of the above compounds to each test tube.
3. Stir the samples.
4. In the chart provided record if each compound is solubility in water.
5. Clean the lab workspace.
Part D %u2013 Conductivity
1. Obtain six 100ml beakers and add 50ml of water to each.
2. Place a 10g sample of each of the above compounds in a separate beaker.
3. Obtain six conductivity meters. Measure and record the conductivity of 4. each solution.
5. Clean the lab workspace.
Observations:
Record the data collected from this experiment in the following chart:
Rank melting point from highest to lowest, where no melting is high and decomposes is low.
Solubility is recorded as %u201Csoluble%u201D or %u201Cinsoluble.%u201D
Conductivity is recorded as %u201Cyes%u201D or %u201Cno.%u201D
Calcium Chloride
Melting Point:
Solubility (water):
Solubility (Ethanol):
Conductivity:
Citric Acid
Melting Point:
Solubility (water):
Solubility (Ethanol):
Conductivity:
Phenyl Salicylate
Melting Point:
Solubility (water):
Solubility (Ethanol):
Conductivity:
Potassium Iodide
Melting Point:
Solubility (water):
Solubility (Ethanol):
Conductivity:
Sodium Chloride
Melting Point:
Solubility (water):
Solubility (Ethanol):
Conductivity:
Sucrose
Melting Point:
Solubility (water):
Solubility (Ethanol):
Conductivity:
Analysis:
From the data table above, separate the compounds into two groups as indicated below:
Group 1(Low Melting Point, Soluble in Ethanol, Not Conductive)
Group 2 (High Melting Point, Soluble in Water, Conductive)
Calcium Chloride:
Citric Acid:
Phenyl Salicylate:
Potassium Iodide:
Sodium Chloride:
Sucrose:
From your knowledge of ionic and covalent bonds classify the following compound as %u201Cionic%u201D or %u201Ccovalent%u201D:
Calcium Chloride:
Citric Acid:
Phenyl Salicylate:
Potassium Iodide:
Sodium Chloride:
Sucrose:
Explanation / Answer
CALCIUM CHLORIDE:
Melting Point:772 celcius(no)
Solubility (water):soluble
Solubility (Ethanol):insoluble
Conductivity:strong conductor(166.08)
CITRIC ACID:
Melting Point:153 celcius(2 nd)
Solubility (water):soluble
Solubility (Ethanol):insoluble(soluble in anhydrous ethanol)
Conductivity:no(weak conductor)
PHENYL SALICYLATE:
Melting Point:41.5 celcius(1 st)
Solubility (water):insoluble
Solubility (Ethanol):soluble
Conductivity: not conductive
POTASSIUM IODIDE:
Melting Point:681 celcius(no)
Solubility (water):soluble
Solubility (Ethanol):insoluble
Conductivity:strong conductor(131.23)
SODIUM CHLORIDE:
melting point:801 celcius(no)
Solubility (water):soluble
Solubility (Ethanol):insoluble
Conductivity:very strong conductor(269.81)
SUCROSE:
Melting Point:186 celcius(3 rd)
Solubility (water):soluble
Solubility (Ethanol):soluble
Conductivity:no
Analysis:
Group 1: citric acid , phenyl salicylate , sucrose
Group 2: calcium chloride, potassium iodide , sodium chloride
Calcium Chloride:Group 2
Citric Acid:Group 1
Phenyl Salicylate:Group 1
Potassium Iodide:Group 2
Sodium Chloride:Group 2
Sucrose:Group 1
Calcium Chloride:ionic
Citric Acid:covalent
Phenyl Salicylate:covalent
Potassium Iodide:ionic
Sodium Chloride:ionic
Sucrose:covalent
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