Diffusion and Kinetic Particle Theory

Flashcards covering the concept of diffusion, factors affecting diffusion rate, gas and liquid experiments, and relative molecular mass calculations.

Diffusion

The process by which different fluids mix as a result of the random motions of their particles.

Mass of the substance (Factor in Diffusion)

The lighter the substance, the faster it diffuses.

Temperature (Factor in Diffusion)

The more kinetic energy the particles have, the faster they move and diffuse.

Presence of other substance (Factor in Diffusion)

Diffusion is faster in an area where there are fewer particles of other substances present, making diffusion extremely fast in vacuums.

Intermolecular spaces (Factor in Diffusion)

Factor explaining why gases diffuse faster than liquids and why solids do not diffuse.

Bromine liquid diffusion experiment

A cylinder containing bromine liquid is sealed with an inverted cylinder above it; when the bromine liquid evaporates, removing the separating lid causes brown bromine gas to diffuse upwards, filling the available space.

Dissolving stage (Potassium Permanganate)

The solid crystal breaks apart into purple permanganate ions ($MnO_4^-$) and potassium ions ($K^+$), creating a dense region of intense purple color at the source.

Equilibrium stage (Potassium Permanganate)

Over time, the entire liquid turns a uniform light purple color, meaning the particles have achieved an even distribution.

Particle Size (Factor in Liquid Diffusion)

Smaller crystals or powdered $KMnO_4$ dissolve and spread through the liquid more quickly than large, dense crystals.

Relative molecular mass effect on diffusion

The less molecular mass a substance has, the faster it will diffuse because it is lighter and covers a longer distance.

Diffusion of ammonia and hydrogen chloride

An experiment where a white cloud appears in a glass tube, demonstrating that ammonia diffuses faster than hydrogen chloride because it has a lower molecular mass.

Solid in liquid key terms (1-D D S S R)

Dissolve, Diffusion, spread, slowly and randomly.

Liquid in liquid key terms (2-M D S S R)

Mixing, Diffusion, spread, slowly and randomly.

Gas key terms (3-E D S F F R)

Evaporation, Diffusion, spread, fast, free and randomly.

Relative molecular mass calculation for $C_3H_8$

Calculated as $(12 \times 3) + (1 \times 8) = 44$.

Relative molecular mass calculation for $NO_2$

Calculated as $(14 \times 1) + (16 \times 2) = 46$.

Kinetic particle explanation for smelling a flower

Scent particles from the flower move randomly in the air, spreading out and traveling through the air until they reach your nose via diffusion.