Interpretation:
The answer that explains the higher boiling point of methanol than ethane or fluoro-methane, even though their molecular weights are nearly equal, is to be selected.
Concept introduction:
A hydrocarbon is organic compound consisting entirely of hydrogen and carbon.
The temperature at which the vapour pressure of the liquid is equal to the pressure exerted on the liquid by the surrounding atmosphere is called boiling point.
A hydrogen bonding is a partially electrostatic force of attraction between a hydrogen atom that is bound to more electronegative atom such as nitrogen, oxygen or fluorine and another atom bearing a lone pair of electrons.
A molecular formula consists of the
Higher the molecular mass of a hydrocarbon, higher will be its boiling point.
An unbranched alkane has a higher boiling point than branched
The alcohol of the same molecular weight has a higher boiling point due to the presence of hydrogen bonding in alcohols.
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Organic Chemistry
- Examining the crystal structure of CsCl (Caesium Chloride), the Cs+ions form the 8 corners of a cube and the Cl−ion is a the center of the cube. From first-principles calculation, it was determined that the lattice constant of CsCl is 4.209 ̊A. (a) Calculate in detail the electrostatic force exerted by all the Cs+ atoms to the Cl−atom; (b) Assuming that 1 Cs+atom is missing in crystal structure (crystal is said to have a defect), calculate in detail what will be the net electrostatic force on the Cl−ion due to the remaining Cs+ions.arrow_forwardWhich type of intermolecular force accounts for each of these differences? (a) CH3OH boils at 65 °C; CH3SH boils at 6 °C. (b) Xe is a liquid at atmospheric pressure and 120 K, whereas Ar is a gas under the same conditions. (c) Kr, atomic weight 84 amu, boils at 120.9 K, whereas Cl2, molecular weight about 71 amu, boils at 238 K. (d) Acetone boils at 56 °C, whereas 2-methylpropane boils at -12 °C. CH3 CH3 O C CH3 CH3 CH3 CH Acetone 2-Methylpropanearrow_forwardBased on the type or types of intermolecular forces, predictthe substance in each pair that has the higher boiling point:(a) propane (C3H8) or n-butane (C4H10), (b) diethyl ether(CH3CH2OCH2CH3) or 1-butanol (CH3CH2CH2CH2OH),(c) sulfur dioxide (SO2) or sulfur trioxide (SO3), (d) phosgene(Cl2CO) or formaldehyde (H2CO).arrow_forward
- Rank the following in order of decreasing(a) Boiling point: O₂, Br₂, As(s)(b) ΔH(vap): Cl₂, Ar, I₂arrow_forwardName the type(s) of intermolecular forces that exists between molecules (or basic units) in each of the following species: (a) NaCL (b) CS2arrow_forwardWhich of the following gases is expected to be most soluble in water? Explain your reasoning.(a) CH4(b) CCl4(c) CHCl3arrow_forward
- Name the type(s) of intermolecular forces that exists between molecules (or basic units) in each of the following species: (a) benzene (C6H6) (b) CH3Cl (c) PF3arrow_forwardAspirin has a higher molar mass compared to salicylic acid, however aspirin melts at a lower temperature than salicylic acid. Provide a brief explanation for this observation. Table 1 Compound: Formula: Salicylic Acid C;H6O3 Aspirin C9H3O4 Molar Mass: 138.12 Melting point: Ka 158-160°C 1.08 x 10³ 180.15 140-142°C 2.72 x 10$ pKa Solubility (g/100ML) 2.99 4.57 0.18 0.25arrow_forward2S03(g) →2SO2(g) + O2(g); AH° =arrow_forward
- For each compound in the table below, decide whether there would be any hydrogen-bonding force between molecules of the compound, or between molecules of the compound and molecules of water. name methanimine acetic acid compound hydrogen fluoride formula or Lewis structure H H-C=N-H H :0: |_|| H-C-C-O-H | H HF Between molecules of the compound? O O O O yes no yes no yes hydrogen-bonding force no Between molecules of the compound and molecules of water? yes no yes no yes no Xarrow_forwardArrange the following compounds in the order of decreasing (highest to lowest) strength of London dispersion forces. (a) CCI4, CF4, CBr4(b) CH4, CH3CH3, CH3CH2CH3(c) Ar, He, Nearrow_forwardThe Dumas method was used to determine the molar mass of an unknown volatile liquid. Atmospheric pressure was 1.000 atm. Volume of flask was measured as 248 mL. Water bath was maintained at boiling temperature until liquid completely evaporated. Then the flask was cooled down. Mass of condensed vapor was determined as 0.4704 g. The liquid is likely to be: (A) Acetone, (CH3)2CO (B) Isopropanol C3H7OH (C) Diethyl ether (C2H5)2O (D) Isooactane C8H18arrow_forward
- Introduction to General, Organic and BiochemistryChemistryISBN:9781285869759Author:Frederick A. Bettelheim, William H. Brown, Mary K. Campbell, Shawn O. Farrell, Omar TorresPublisher:Cengage Learning