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Examoogle • User • info@examoogle.com • EE-2024-8821
Chapter 1 of 12 • Page 1 of 248🔒 Protected PDF • Watermarked
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When a drop of ink is placed in water, it spreads evenly without stirring. What does this demonstrate?
Particles are at rest
Water reacts with ink
Particles of matter are constantly moving
Particles are heavy and settle down
Particles are at rest
The spreading of ink in water is a classic demonstration of the kinetic molecular theory, specifically diffusion. This phenomenon occurs because particles of matter possess kinetic energy and are in constant, random motion, causing them to collide and redistribute until the ink concentration is uniform throughout the liquid.
The spreading of ink in water is a classic demonstration of the kinetic molecular theory, specifically diffusion. This phenomenon occurs because particles of matter possess kinetic energy and are in constant, random motion, causing them to collide and redistribute until the ink concentration is uniform throughout the liquid.
Think of a drop of food coloring in a glass of water or the way the smell of perfume spreads across a room; in both cases, the particles move from a dense source to fill the available space naturally.
KE=21mv2 — Kinetic energy of particles which dictates the speed of diffusion
This occurs due to diffusion, the net movement of particles from a region of higher concentration to a region of lower concentration. Even without external agitation (stirring), the thermal energy of water molecules causes them to collide with ink particles. These random, constant collisions (Brownian motion) drive the ink particles to migrate through the interstitial spaces of the water molecules until a state of dynamic equilibrium is reached.
Diffusion increases with an increase in temperature as kinetic energy rises.
Particles move from a region of higher concentration to lower concentration.
No external energy (stirring) is required for diffusion in liquids and gases.
Explains how nutrients reach cells in living organisms
Explains how oxygen enters the blood via the alveoli
Mixing of fragrances in the air
Movement of oxygen into the lungs during respiration
The provided Official Answer Key (Option A) is factually incorrect based on the Kinetic Molecular Theory.
Option B is incorrect because ink and water form a mixture, not a chemical reaction.
Option D is incorrect because the ink particles remain suspended and dispersed, they do not settle like sediment.
Option C is correct — The process of diffusion demonstrates that particles of matter are in constant random motion.
Always remember that in science exams, if an official answer key conflicts with a fundamental theory (like Kinetic Theory), the scientific fact takes precedence, though you must answer according to the expected logic of the board.