Chemistry Exam 6 Flashcards

Heating Curve of Sucrose

• Sucrose has a molar mass of 342.30 g/mol, with specific heat capacities of 430 J/mol·K for the solid phase.
• Melting point is 462 K, and boiling point is 1290 K.
• Portion A indicates heating of solid sucrose with an increase in potential energy.
• Portion B shows the phase transition from solid to liquid, reflecting an increase in kinetic energy.
• Portion C represents the kinetic energy increase in the gas phase of sucrose.

Functional Groups in Aspirin

• Aspirin contains a carboxylic acid and an ester functional group.
• No presence of alcohol, amine, aldehyde, or amide functional groups in aspirin.

Ion Heat of Hydration

• Calcium ion (Ca2+) has the largest (most negative) heat of hydration, indicating a strong interaction with water.

Enthalpy Diagram for Ionic Compound

• Arrow B on the diagram represents exothermic enthalpy of mixing.
• Arrow C illustrates heat of solution, which is also exothermic.
• The ionic compound will dissolve regardless of small entropy changes, and dissolving occurs if the entropy change surpasses enthalpy costs.

Phase Diagram Insights

• Area A represents the solid phase of the substance.
• Decreasing pressure from 10 to 0 atm at -60°C leads to sublimation.
• The critical point is at 31°C, indicating a unique state for the substance.
• At 1 atm, no temperature allows for a liquid phase of the substance.

Solubility Predictions

• Ammonia (NH3) is more soluble in water compared to propane (CH3CH2CH3).
• Bromine (Br2) is predicted to be more soluble in hexane (C6H14) than dichloromethane (CH2Cl2).

Heat Energy Calculation for Ethanol

• Calculating the heat energy to raise a 51.4 g sample of ethanol from -150°C to 55°C results in an energy need of 27.5 kJ.

Saturated Solutions Insights

• In a saturated solution of nitrogen (N2), decreasing temperature increases its concentration.
• For magnesium iodide (MgI2), a decrease in pressure does not change its concentration.

C6H14 Isomer with Highest Boiling Point

• The isomer of hexane (C6H14) with the highest boiling point is characterized by its branched structure.

Calculating Molality of HNO3 Solution

• The molality of a 1.87 M HNO3 aqueous solution is determined to be 1.52.

CO2 Solubility in Water and Henry's Law

• Using Henry's law, it’s calculated that 1.88 g of CO2 will dissolve in 5.50 L of water at a partial pressure of 0.235 atm.