A Lower Tank Contains Water While an Upper Tank Contains

question 38

Multiple Choice

A lower tank contains water while an upper tank contains air with a negligible concentration of water vapor. A tube with a circular cross section and radius 0.050 m is inserted between the two tanks. The length of the tube is 0.25 m. The diffusion coefficient of water vapor through air is 2.4 × 10^-5 m²/s. The concentration of water vapor just above the surface of the water is 1.7 × 10^-2 kg/m³. If the water vapor is removed from the upper tank so that the concentration there remains nearly zero, what mass of water vapor diffuses through the tube each hour?

• A)4.6 × 10^-5 kg
• B)2.0 × 10^-6 kg
• C)7.1 × 10^-7 kg
• D)1.3 × 10^-8 kg
• E)8.2 × 10^-8 kg

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Definitions:

Hierarchy of Fears

A theoretical framework suggesting that fears can be organized in a hierarchical fashion, ranging from less to more intense, which can be useful in treatments like systematic desensitization.

Astraphobia

The intense fear of thunder and lightning.

Systematic Desensitization

A behavior therapy used to reduce phobic reactions through gradual exposure to feared stimuli or situations combined with relaxation techniques or coping mechanisms.

Traumatic

Pertaining to or resulting from an event that causes severe emotional stress or physical injury.