Table of contents

1. Intro to General Chemistry3h 48m
2. Atoms & Elements4h 16m
3. Chemical Reactions4h 10m
4. BONUS: Lab Techniques and Procedures1h 38m
5. BONUS: Mathematical Operations and Functions48m
6. Chemical Quantities & Aqueous Reactions3h 53m
7. Gases3h 49m
8. Thermochemistry2h 37m
9. Quantum Mechanics2h 58m
10. Periodic Properties of the Elements3h 9m
11. Bonding & Molecular Structure3h 29m
12. Molecular Shapes & Valence Bond Theory1h 57m
13. Liquids, Solids & Intermolecular Forces2h 23m
14. Solutions3h 1m
15. Chemical Kinetics2h 53m
16. Chemical Equilibrium2h 29m
17. Acid and Base Equilibrium5h 1m
18. Aqueous Equilibrium4h 47m
19. Chemical Thermodynamics1h 50m
20. Electrochemistry2h 42m
21. Nuclear Chemistry2h 36m
22. Organic Chemistry5h 7m
23. Chemistry of the Nonmetals2h 39m
24. Transition Metals and Coordination Compounds3h 16m

13. Liquids, Solids & Intermolecular Forces

Heating and Cooling Curves

General Chemistry

13. Liquids, Solids & Intermolecular Forces

Heating and Cooling Curves

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Multiple Choice

Determine the vapor pressure (atm) of rubbing alcohol (isopropanol) at 20.0℃. The normal boiling point of isopropanol is 82.3℃ and the heat of vaporization (ΔH_vap) is 39.9 kJ/mol.

1.35 × 10⁻³ atm

5.67 × 10⁻² atm

9.97 × 10⁻¹ atm

17.6 atm

43.1 atm

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Verified step by step guidance

Identify the given values: the normal boiling point of isopropanol (T1 = 82.3°C), the heat of vaporization (ΔHvap = 39.9 kJ/mol), and the temperature at which you need to find the vapor pressure (T2 = 20.0°C).

Convert the temperatures from Celsius to Kelvin by adding 273.15 to each temperature. This gives T1 = 355.45 K and T2 = 293.15 K.

Use the Clausius-Clapeyron equation to relate the vapor pressures at two different temperatures: \( \ln \left( \frac{P_2}{P_1} \right) = \frac{-\Delta H_{\text{vap}}}{R} \left( \frac{1}{T_2} - \frac{1}{T_1} \right) \), where R is the ideal gas constant (8.314 J/mol·K).

Rearrange the equation to solve for \( P_2 \), the vapor pressure at 20.0°C: \( P_2 = P_1 \cdot \exp \left( \frac{-\Delta H_{\text{vap}}}{R} \left( \frac{1}{T_2} - \frac{1}{T_1} \right) \right) \).

Assume the vapor pressure at the boiling point (P1) is 1 atm, as it is the normal boiling point. Substitute the values into the equation and solve for P2.