predict the order of increasing vapor pressure at a given temperature for the following compounds: a.ch3ch2ch2ch2oh , b.ch3ch2och2ch3 , c.hoch2ch2ch2oh
HO-CH₂ CH₂ CH₂-OH < CH₃CH₂ CH₂ CH₂-OH < CH₃CH₂-O-CH₂ CH₃
Hydrogen Bonding decreasing => Vapor Pressure increasing
The -OH group promotes H-Bonding.
To predict the order of increasing vapor pressure at a given temperature for the given compounds, we need to consider the molecular structure and intermolecular forces. The strength of intermolecular forces influences vapor pressure, with weaker forces resulting in higher vapor pressure.
Here's a step-by-step guide on how to determine the order:
1. Identify the molecular structures of the compounds:
a. CH3CH2CH2CH2OH: This is butanol, an alcohol, with the formula C4H9OH.
b. CH3CH2OCH2CH3: This is ethoxyethane, also known as diethyl ether, with the formula C4H10O.
c. HOCH2CH2CH2OH: This is 1,2-ethanediol or ethylene glycol, with the formula C2H6O2.
2. Consider intermolecular forces:
- Butanol (CH3CH2CH2CH2OH) can form hydrogen bonds due to the presence of the hydroxyl (-OH) group. Hydrogen bonding is a strong intermolecular force.
- Ethoxyethane (CH3CH2OCH2CH3) and ethylene glycol (HOCH2CH2CH2OH) do not have hydroxyl groups, so they cannot exhibit hydrogen bonding. They primarily experience weaker London dispersion forces and dipole-dipole interactions.
3. Compare the strength of intermolecular forces:
- Butanol (CH3CH2CH2CH2OH) has the strongest intermolecular forces due to hydrogen bonding.
- Ethylene glycol (HOCH2CH2CH2OH) has dipole-dipole interactions but no hydrogen bonding.
- Ethoxyethane (CH3CH2OCH2CH3) has the weakest intermolecular forces, only exhibiting London dispersion forces.
4. Order the compounds based on intermolecular forces:
Based on the strength of intermolecular forces from strongest to weakest, the order of increasing vapor pressure at a given temperature is:
1. CH3CH2OCH2CH3 (ethoxyethane)
2. HOCH2CH2CH2OH (ethylene glycol)
3. CH3CH2CH2CH2OH (butanol)
Therefore, the predicted order of increasing vapor pressure at a given temperature is: ethoxyethane < ethylene glycol < butanol.