Questions: 5-8 Identification of five unknown compounds 5- Describe the intermol
ID: 854202 • Letter: Q
Question
Questions: 5-8
Identification of five unknown compounds
5- Describe the intermolecular forces that are present in a pure sample of each of the compounds.
*- Cyclohexane :
*- Citric acid:
*- Methanol:
*-Sodium chloride:
*- Benzophenone:
For each of the compounds, describe the intermolecular forces that exist between it and the solvent(s) in which it was soluble.
*- Cyclohexane:
*- Citric acid:
*- Methanol:
*-Sodium chloride:
*- Benzophenone:
Use your understanding of intermolecular forces to thoroughly explain the differences and trends in the physical properties of the five compounds. 32
8. How could your method be improved? Explain how your proposed changes would improve the accuracy, precision, safety, or efficiency of the experiment.
Explanation / Answer
pure cyclo hexane:It has london dispersion forces.
The London dispersion force is the weakest intermolecular force. The London dispersion force is a temporary attractive force that results when the electrons in two adjacent atoms occupy positions that make the atoms form temporary dipoles. This force is sometimes called an induced dipole-induced dipole attraction. London forces are the attractive forces that cause nonpolar substances to condense to liquids and to freeze into solids when the temperature is lowered sufficiently.
Citric acid can form Hydrogen bonds
Hydrogen bonding - special case of dipole-dipole when there is a H bonded to a N, O, or F. Hydrogen bonds are formed between an electronegative atom of one molecule and a Hydrogen atom of another molecule (Intermolecular) OR an an electronegative atom of one molecule and the Hydrogen of the same molecule. In the case of citric acid, it is Intermolecular Hydrogen Bonding between citric acid and water.
methanol:The primary intermolecular force present in methanol is hydrogen bonding.
There are three intermolecular forces that occur in covalent compounds:1)Dipole-dipole forces (Interaction of polar molecules with other polar molecules)
2)Hydrogen bonds 3)London dispersion forces .
sodium chloride:Ionic - result of electrostatic forces between ions(na+,cl-).
benzophenon:have dipole-dipole forces and London/dispersion forces.
Cyclohexane :is insoluble in everything, and is considered an inert compound.
And also do not interact with water thru hydrogen bondingn also they are also highly non-polar
Citric acid is indeed polyprotic, in simple terms, it can release 3 H+ ions into solution.so it is dissolved in water by forming hydrogen bonding.
methanol in water:Hydrogen bridges (C-O-H) in methanol and water (H-O-H) 'like' each other (attraction!) because of hydrogen bonding.
sodium chloride:
IONIC SOLUTE - POLAR SOLVENT:
When an ionic crystal such as NaCl is placed in water, a dissolving reaction will occur. Initially, the positive and negative ion are only attracted to each other. The water molecules are hydrogen bonded to each other. If the crystal is to dissolve, these bonds must be broken.
Negative chloride ions on the surface are attracted by neighboring positive sodium ions and by the partially positive hydrogen atom in the polar water molecule (See the graphic on the right).
Similarly, the positive sodium ions are attracted by both chloride ions and the partially negative oxygen atom in the polar water molecule. (See the graphic on the right).
A "tug-of-war" occurs for the positive and negative ions between the other ions in the crystal and the water molecules. Whether the crystal dissolves is determined by which attractive force is stronger. If the internal ionic forces in the crystal are the strongest, the crystal does not dissolve. This is the situation in reactions where precipitates form. If the attractions for the ions by the polar water molecules are the strongest, the crystal will dissolve. This is the situation in sodium chloride.
Once the ions are released from the crystals, the ions are completely surrounded by water molecules. Note that the proper atom in the water molecule must "point" toward the correct ion. The charge principle and the partial charges in the polar molecule determine the correct orientation.
benzophenon: benzophenone will dissolve more because the carbonyl group can at least form two hydrogen bonds (from the two lone pairs of the oxygen) and methanol is a hydrogen-bonding solvent.
important thing is like dissolves likes:
This means that ionic or polar solutes dissolve in polar solvents.
Non-polar solutes dissolve in non-polar solvents.
Polar and ionic solutes DO NOT dissolve in non-polar solvents and vice versa.
1)IONIC SOLUTE - POLAR SOLVENT
2)POLAR SOLUTE - POLAR SOLVENT
3)NON-POLAR SOLUTE - NON-POLAR SOLVENT
4)NON-POLAR SOLUTE - POLAR SOLVENT
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