-Draw Lewis structure of CH3CH2COOH (propanoic acid). -Determine electron pair geometry, bond angle and hybridization for each atom. Explain the answer -Identify if the molecule is polar. Explain why or why not? -What type of intermolecular forces would present in a liquid sample of propanoic acid? Explain. -Draw the strongest intermolecular forces present in the sample from part d. -Draw Lewis structure of CH3CH2CH2CH3 (butane). -Determine electron pair geometry, bond angle and hybridization for each atom. Explain the answer -Identify if the molecule is polar. Explain why or why not? -What type of intermolecular forces would present in a liquid sample of propanoic acid? Explain. -Draw the strongest intermolecular forces present in the sample from part d.
The Correct Answer and Explanation is:
. Lewis Structure of CH3CH2COOH (Propanoic Acid):
To draw the Lewis structure of propanoic acid, follow these steps:
- Carbon (C) is the central atom in each group, with hydrogen (H) and oxygen (O) attached accordingly.
- Each carbon forms a single bond to hydrogen (except for the carboxyl group, where it bonds with oxygen).
- The carboxyl group (-COOH) consists of a C double-bonded to O and bonded to a hydroxyl group (-OH).
The structure:
mathematicaCopyEdit H H
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H3C - CH2 - C = O
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OH
2. Electron Pair Geometry, Bond Angles, and Hybridization:
- CH3 (Methyl group): The central carbon is sp3 hybridized, as it forms single bonds with three hydrogen atoms. The electron pair geometry is tetrahedral with a bond angle of approximately 109.5°.
- CH2 (Methylene group): The central carbon is sp3 hybridized and forms two single bonds—one with hydrogen and the other with the adjacent carbon. The electron pair geometry is tetrahedral with bond angles near 109.5°.
- COOH (Carboxyl group): The carbon in the carboxyl group is sp2 hybridized because it forms a double bond with oxygen and a single bond with hydroxyl (OH). The electron pair geometry is trigonal planar with bond angles of approximately 120°.
3. Is Propanoic Acid Polar?
Yes, propanoic acid is polar. The molecule has a polar carboxyl group (-COOH) with a significant difference in electronegativity between carbon and oxygen. Oxygen pulls electron density from the carbon, creating a dipole moment. Additionally, the presence of a hydroxyl group (-OH) makes the molecule polar, as it can form hydrogen bonds.
4. Intermolecular Forces in Propanoic Acid:
In a liquid sample of propanoic acid, hydrogen bonding is the primary intermolecular force due to the presence of the -OH group. Additionally, dipole-dipole interactions exist between the polar carboxyl groups, and London dispersion forces are present due to the presence of electrons and the nonpolar alkyl groups.
5. Drawing Intermolecular Forces in Propanoic Acid:
mathematicaCopyEditH O H
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C - C - O
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H H
Hydrogen bonds occur between the hydrogen atom of the hydroxyl group and the oxygen atom of another molecule.
6. Lewis Structure of CH3CH2CH2CH3 (Butane):
To draw the Lewis structure of butane, follow the same steps as above:
- Carbon atoms form single bonds with each other and hydrogen atoms.
The structure:
nginxCopyEdit H H H H
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H3C - CH2 - CH2 - CH3
7. Electron Pair Geometry, Bond Angles, and Hybridization:
- CH3 (Methyl group): The central carbon is sp3 hybridized, as it forms single bonds with three hydrogen atoms. The electron pair geometry is tetrahedral with a bond angle of approximately 109.5°.
- CH2 (Methylene group): The central carbon is sp3 hybridized and forms two single bonds—one with hydrogen and the other with the adjacent carbon. The electron pair geometry is tetrahedral with bond angles near 109.5°.
8. Is Butane Polar?
No, butane is nonpolar. The molecule consists of only carbon-carbon and carbon-hydrogen bonds, which have negligible differences in electronegativity. Thus, there is no significant dipole moment.
9. Intermolecular Forces in Butane:
In a liquid sample of butane, London dispersion forces are the dominant intermolecular forces. These forces arise due to the temporary shifts in electron density within the molecules. Since butane is nonpolar, there are no dipole-dipole interactions or hydrogen bonds.
10. Drawing Intermolecular Forces in Butane:
Butane only experiences London dispersion forces, which are too weak to be drawn explicitly in a diagram but can be represented as temporary shifts in electron density between molecules.
To summarize:
- Propanoic acid is polar and exhibits hydrogen bonding and dipole-dipole interactions.
- Butane is nonpolar and only experiences London dispersion forces.
