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

8. Thermochemistry

Thermal Equilibrium

General Chemistry

8. Thermochemistry

Thermal Equilibrium

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Multiple Choice

How much energy is needed to vaporize 75.0 g of diethyl ether (C4H10O) at its boiling point (34.6 °C), given that ΔHvap of diethyl ether = 26.5 kJ/mol?

34.5 kJ

68.1 kJ

26.5 kJ

102.3 kJ

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Verified step by step guidance

First, determine the molar mass of diethyl ether (C4H10O). Calculate the molar mass by adding the atomic masses of all the atoms in the formula: Carbon (C) has an atomic mass of approximately 12.01 g/mol, Hydrogen (H) is about 1.01 g/mol, and Oxygen (O) is about 16.00 g/mol. Therefore, the molar mass of C4H10O is: 4(12.01) + 10(1.01) + 16.00.

Next, convert the mass of diethyl ether from grams to moles using its molar mass. Use the formula: \( \text{moles} = \frac{\text{mass (g)}}{\text{molar mass (g/mol)}} \). Substitute the given mass of diethyl ether (75.0 g) and the calculated molar mass from the previous step.

Now, use the enthalpy of vaporization (ΔHvap) to calculate the energy required to vaporize the given amount of diethyl ether. The formula to use is: \( \text{Energy (kJ)} = \text{moles} \times \Delta H_{\text{vap}} \). Substitute the number of moles calculated in the previous step and the given ΔHvap (26.5 kJ/mol).

Ensure that the units are consistent throughout the calculation. The mass was converted to moles, and the energy is calculated in kilojoules (kJ), which matches the units of ΔHvap.

Finally, interpret the result to understand the amount of energy required to vaporize 75.0 g of diethyl ether at its boiling point. This involves understanding that the calculated energy represents the heat absorbed during the phase change from liquid to gas at the boiling point.