Apentix/AP Chemistry/Unit 3: Intermolecular Forces and Properties/Question
AP Chemistrymediummcq1 pt

A narrow glass capillary dipped into water draws the liquid upward well above the surrounding level. Which combination of effects produces this capillary rise?

A.Adhesion of water to glass acting alone
B.Cohesion among water molecules combined with adhesion of water to the polar glass surface
C.Elevated vapor pressure pushing liquid upward from beneath
D.Mutual repulsion among water molecules squeezing liquid into the tube

Explanation

Core Concept

Capillary rise requires both forces working in concert. Adhesion between water and polar glass drags the meniscus edges upward, curving the surface. Cohesion then transmits that pull through the connected hydrogen-bonded network, lifting the entire column until its weight balances the upward force. Narrower tubes raise water higher because less weight accompanies the same wall contact, and plastic tubes show little rise because adhesion there is weak.

Correct Answer

BCohesion among water molecules combined with adhesion of water to the polar glass surface

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