Asked by mimi

SEP Analyze Date Look at Figure 1. In summer, at which depth, A, B, or C, is the water likely to be (a) most dense? (b) least dense? Explain why this is so in terms of the spaces between molecules. (Hint: Think about where the water is the coldest as a lake freezes.) Use what you know about kinetic molecular theory in your answer.

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Answered by GPT-5 mini AI
Assuming A is the surface, B mid-depth, C bottom:

(a) Most dense: C (bottom).
(b) Least dense: A (surface).

Why: Density depends on mass per unit volume — how closely the molecules are packed. In summer the surface (A) is warmed by the sun, so molecules have higher kinetic energy, move faster and on average are farther apart (more space between molecules) → lower density. Deeper water (C) stays much colder (often near 4 °C in lakes), so the molecules have less kinetic energy and are packed more closely together (fewer spaces) → higher density. B would be intermediate. (Remember water is anomalous: it is densest near 4 °C, which is why the coldest water and ice stay at the top when a lake freezes.)