Conductivity of Solutions Virtual Lab Background: Some properties may be used to predict the type of bonding in a substance. These properties are phase at room temperature, melting point, solubility in water and electrical conductivity. Atoms can bond by either the transfer of electrons or the sharing of electrons. Atoms which transfer electrons form ionic bonds while those which share electrons form covalent bonds. A conductivity apparatus will be used in this experiment to determine if a substance conducts electricity. When the electrodes of the conductivity appartus are placed into a substance that conducts electricity the bulb will light up. This occurs because electricity travels from one electrode through the substance to the second electrode completing the circuit and lighting the bulb. If the substance does not conduct electricity then the circuit is not completed and the bulb will not light up. Objective: Several physical properties of different compounds will be demonstrated. By comparing the patterns that develop, students will determine which properties are related to the particular type bonding. Substance Conducts Electricity Substance Does Not Conduct Electricity Properties of Ionic Compounds Crystalline solids (made of ions) High melting and boiling points Conduct electricity when in aqueous solution Many soluble in water but not in nonpolar liquid Conduct electricity in water Properties of Covalent Compounds Gasses, liquids, or solids (made of molecules) Low melting and boiling points Poor electrical conductors in all phases Many soluble in nonpolar liquids but not in water Prelab: Define the following: Ionic bonds: Electrolyte: Electronegativity: Procedure: Each of the following substances was tested using a conductivity tester. Click on the link "click to view results" to see the results of the conductivity tests for each substance. You will use the data collected and your knowledge of Chemistry to determine the type bonding found in each substance. Hint: Review the properties of ionic and covalent compounds listed above. Data: Substance Type of Bonding Phase @ Room Temp. Melting Point (C) Electrical Conductivity without Water Electrical Conductivity in Water Solubility in water (does it dissolve) Distilled water Covalent L 0 View Results View Results N/A Sodium Chloride (NaCl) Ionic S 808 View Results View Results yes Potassium Iodide (KI) Ionic S 680 View Results View Results yes Sucrose (C12H22O11) glycosidic S 186 View Results View Results yes Olive Oil covalent L -6 View Results View Results No Ethanol (C2H6O) Non polar covalent L -114 View Results View Results yes Corn starch hydrogen S Decomposes @ high temps View Results View Results no Glycerin hydrenog L 17.8 View Results View Results no Calcium Chloride (CaCl2) ionic S 772.2 View Results View Results yes Sodium chloride is an ionic compound while corn starch is a covalent. Go back to your chart and determine which other compounds are ionic compounds. What characteristics do these ionic compounds have in common that caused you to choose them? (Hint: Refer to the properties of ionic and covalent compounds in the prelab) The substances you have not selected as ionic compounds are covalent compounds. What characteristics do the covalent compounds have in common? (Hint: Refer to the properties of ionic and covalent compounds in the prelab) Water is what is known as a polar covalent substance and it can dissolve other polar, covalent substances. Which substances are polar, covalent compounds? (Hint: Which substances are soluable in water) Water will no dissolve covalent substances which are non polar. Which substances are non polar? (Hint which subsstances are insoluable in water)(Hint: Refer to the properties of ionic and covalent compounds in the prelab) Analysis: What phase were all your ionic compounds in? Why? Why are the melting points of the ionic compounds so much higher than water’s melting point? When are ionic compounds able to conduct electricity? Why? If water doesn’t conduct electricity, why would you get electrocuted if you drop your hair dryer in the bathtub when you’re in it? Look at the ionic compounds you identified. Using your periodic table, determine what types of elements are found in ionic compounds. Write out the Lewis dot diagrams for the ionic compounds in the table above.

Question

Conductivity of Solutions Virtual Lab

Background:

Some properties may be used to predict the type of bonding in a substance. These properties are phase at room temperature, melting point, solubility in water and electrical conductivity. Atoms can bond by either the transfer of electrons or the sharing of electrons. Atoms which transfer electrons form ionic bonds while those which share electrons form covalent bonds.

A conductivity apparatus will be used in this experiment to determine if a substance conducts electricity. When the electrodes of the conductivity appartus are placed into a substance that conducts electricity the bulb will light up. This occurs because electricity travels from one electrode through the substance to the second electrode completing the circuit and lighting the bulb. If the substance does not conduct electricity then the circuit is not completed and the bulb will not light up.

Objective:

Several physical properties of different compounds will be demonstrated. By comparing the patterns that develop, students will determine which properties are related to the particular type bonding.

Substance Conducts Electricity Substance Does Not Conduct Electricity

Properties of Ionic Compounds

Crystalline solids (made of ions)
High melting and boiling points
Conduct electricity when in aqueous solution
Many soluble in water but not in nonpolar liquid
Conduct electricity in water

Properties of Covalent Compounds

Gasses, liquids, or solids (made of molecules)
Low melting and boiling points
Poor electrical conductors in all phases
Many soluble in nonpolar liquids but not in water

Prelab: Define the following:

Ionic bonds:
Electrolyte:
Electronegativity:

Procedure:

Each of the following substances was tested using a conductivity tester. Click on the link "click to view results" to see the results of the conductivity tests for each substance.

You will use the data collected and your knowledge of Chemistry to determine the type bonding found in each substance. Hint: Review the properties of ionic and covalent compounds listed above.

Data:

Substance	Type of Bonding	Phase @ Room Temp.	Melting Point (C)	Electrical Conductivity without Water	Electrical Conductivity in Water	Solubility in water (does it dissolve)
Distilled water	Covalent	L	0	View Results	View Results	N/A
Sodium Chloride (NaCl)	Ionic	S	808	View Results	View Results	yes
Potassium Iodide (KI)	Ionic	S	680	View Results	View Results	yes
Sucrose (C12H22O11)	glycosidic	S	186	View Results	View Results	yes
Olive Oil	covalent	L	-6	View Results	View Results	No
Ethanol (C2H6O)	Non polar covalent	L	-114	View Results	View Results	yes
Corn starch	hydrogen	S	Decomposes @ high temps	View Results	View Results	no
Glycerin	hydrenog	L	17.8	View Results	View Results	no
Calcium Chloride (CaCl2)	ionic	S	772.2	View Results	View Results	yes

Sodium chloride is an ionic compound while corn starch is a covalent. Go back to your chart and determine which other compounds are ionic compounds. What characteristics do these ionic compounds have in common that caused you to choose them? (Hint: Refer to the properties of ionic and covalent compounds in the prelab)

The substances you have not selected as ionic compounds are covalent compounds. What characteristics do the covalent compounds have in common? (Hint: Refer to the properties of ionic and covalent compounds in the prelab)

Water is what is known as a polar covalent substance and it can dissolve other polar, covalent substances. Which substances are polar, covalent compounds? (Hint: Which substances are soluable in water)

Water will no dissolve covalent substances which are non polar. Which substances are non polar? (Hint which subsstances are insoluable in water)(Hint: Refer to the properties of ionic and covalent compounds in the prelab)

Analysis: