Two Solutions (The System), Each with a Volume of 25

question 21

Multiple Choice

Two solutions (the system) , each with a volume of 25.0 mL at 25.0°C, are mixed in a beaker. A reaction occurs between them, and the temperature rises to 35.0°C. After the products have equilibrated with the surroundings, the temperature is again 25.0°C and the total volume is 50.0 mL. No gases are involved in the reaction. Which relationship concerning the change from initial to final states (both at 25.0°C) is correct?

• A) ΔU = 0
• B) ΔH = 0
• C) ΔU > 0
• D) q = 0
• E) w = 0

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Definitions:

Psychosexual Stages

Freud's theory of developmental stages through which a child's libido is focused on different erogenous zones from birth through adolescence.

Sexual

Pertaining to the biological differences between males and females and activities related to physical attraction or intimate physical contact.

Pleasure-Giving Urge

Denotes an intrinsic motivation or desire to seek activities or stimuli that provide enjoyment, satisfaction, or pleasure.

Defence Mechanisms

Psychological strategies brought into play by individuals, groups, and even nations to cope with realities and to maintain self-image.