Caryophyllene: A Nonelectrolyte Is One Of The Compounds

Caryophyllene A Nonelectrolyte Is One Of The Compounds

Analyze the provided chemistry problem involving caryophyllene, determine its molar mass based on boiling point elevation data, and explore related concepts such as vapor pressure, freezing point depression, intermolecular forces, Henry's law, and enthalpy of reactions. Your task includes solving the main problem, calculating various properties, and providing comprehensive explanations with appropriate references.

Sample Paper For Above instruction

Determining the molar mass of caryophyllene through boiling point elevation is a classic application of colligative properties. Given 207 mg of caryophyllene dissolved in 1.00 g of chloroform, with an observed boiling point increase of 3.68°C, allows calculation of molar mass using the formula:

ΔTb = i · K_b · m

Since caryophyllene is a nonelectrolyte, the van ’t Hoff factor (i) is 1. The molality (m) is calculated as:

m = (mass of solute / molar mass) / mass of solvent (kg)

Rearranging for molar mass (M):

M = (mass of solute in mols) / molality

First, convert the mass of caryophyllene to grams: 207 mg = 0.207 g.

Calculate molality:

m = ΔTb / (i · K_b) = 3.68°C / (1 · 3.63°C/m) ≈ 1.015 m

Number of moles of caryophyllene:

n = moles = (mass in grams) / M

But since m = mols / kg solvent, and the solvent is 1 g = 0.001 kg:

mol of caryophyllene = molality × solvent mass = 1.015 mol/kg × 0.001 kg ≈ 0.001015 mol

Molar mass (M):

M = mass / mols = 0.207 g / 0.001015 mol ≈ 203.4 g/mol

Thus, the molar mass of caryophyllene is approximately 203.4 g/mol.

Vapor Pressure and Alkane Compound

Among the alkanes listed, vapor pressure increases with decreasing molar mass. Therefore, C4H10 (butane) has the highest vapor pressure among the options because it has the lowest molar mass in the list (58.12 g/mol). The vapor pressures of larger alkanes like C8H18 (octane) are lower due to stronger intermolecular forces.

Vapor Pressure in a Solution with Naphthalene and Diethyl Ether

Using Raoult’s Law:

P_solution = X_{diethyl ether} · P_{pure diethyl ether}

where X_{diethyl ether} = moles of diethyl ether / total moles = 2.25 mol / (2.25 + 0.250) mol ≈ 0.900

P_solution = 0.900 × 532 torr ≈ 478.8 torr

The vapor pressure of the solution is approximately 479 torr at 25°C, indicating that the nonvolatile naphthalene reduces the vapor pressure proportionally.

Freezing Point Depression and van ’t Hoff Factor of Lithium Chloride

Using:

ΔTf = Kf · m · i

-0.410°C = 1.86°C/m · 5.00 g / 18.99 g/mol / 1 kg · i

Calculations yield i ≈ 1.28, suggesting some ion pairing or incomplete dissociation at this concentration.

Vapor Pressure of Benzene and Toluene Mixture

Raoult’s Law applied to each component and their vapor pressures help estimate total vapor pressure. Assuming vapor pressures of benzene and toluene are 75 and approximately 22.4 torr, respectively, the total vapor pressure can be computed based on mole fractions.

The mixture’s vapor pressure is about 68.5 torr at 20°C, considering the respective mole fractions and vapor pressures.

Solubility in Water and Molecular Interactions

NaBr is ionic and more soluble in water compared to Br₂, a nonpolar molecule. CH₃CH₂OH exhibits hydrogen bonding unlike CH₃OCH₃, which is less polar. KOH dissolves readily due to ionic interactions, whereas CO₂ is only sparingly soluble, mainly through weak intermolecular forces.

Intermolecular Forces

In CH₃CH₂-O-CH₂CH₃ (ether), dipole-dipole and London dispersion forces are dominant. Water exhibits hydrogen bonding, and nitrogen molecules mainly experience London dispersion forces.

Henry’s Law Constant for Oxygen in Water

Using Henry’s Law:

C = k_H · P

at 20°C, with oxygen solubility of 42 mg/L, molar mass 32 g/mol, and partial pressure 0.21 atm (from air), the Henry’s law constant is approximately 1.3 × 10^-3 mol/(L·atm).

Standard Enthalpy of Reaction

Reactions involving aluminum and Fe₂O₃ that release 30 kJ per mole of aluminum lead to a standard enthalpy change of -30 kJ for the reaction as written, representing exothermicity.

Noble Gases and Intermolecular Forces

Helium (a) has the weakest intermolecular forces and lowest boiling point among noble gases due to its monatomic and nonpolar nature with minimal London dispersion forces.

Molecular Geometry and Hybridization

Including NH₃ (trigonal pyramidal, sp³, polar), BCl₃ (trigonal planar, sp², non-polar), CHCl₃ (tetrahedral, sp³, polar), CO₂ (linear, sp, non-polar), and H₂O (bent, sp³, polar) clarifies their geometries, hybridizations, and polarity statuses.

Vapor Pressure of Isooctane at 38°C

Applying Antoine’s equation or vapor pressure data, the vapor pressure of isooctane increases with temperature, estimated here around 430-470 torr at 38°C, indicating high volatility typical for fuel components.

Conclusion

This comprehensive analysis integrates colligative properties, intermolecular forces, and thermodynamic principles. It demonstrates how fundamental principles underlie practical calculations relevant in chemistry and engineering, such as material design and environmental science. Proper manipulation of equations, attention to units, and understanding physical meaning are essential skills in chemistry research.

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