Understanding Diffusion Processes

Which of the following factors does NOT affect the rate of diffusion?

• Temperature

• Concentration gradient

• Colour of the substance

• Surface area

Answer explanation

The rate of diffusion is influenced by factors like temperature, concentration gradient, and surface area. However, the colour of the substance does not affect diffusion, making it the correct choice.

What happens to the rate of diffusion when the temperature increases?

• It decreases

• It remains the same

• It increases

• It stops completely

Answer explanation

When temperature increases, particles gain kinetic energy, leading to faster movement. This increased motion enhances the rate of diffusion, making it rise. Therefore, the correct answer is that the rate of diffusion increases.

In which state of matter does diffusion occur the fastest?

• Solids

• Liquids

• Gases

• Plasma

Answer explanation

Diffusion occurs fastest in gases because their particles are far apart and move freely, allowing them to spread quickly. In solids and liquids, particles are closer together, which slows down the diffusion process.

Which of the following is an example of diffusion in gases?

• Sugar dissolving in water

• Perfume spreading in a room

• Salt spreading in a soup

• Ice melting

Answer explanation

Perfume spreading in a room is an example of diffusion in gases, as it involves the movement of perfume molecules from an area of higher concentration to lower concentration in the air.

What is the primary reason diffusion occurs more rapidly in gases than in liquids?

• Gases have a higher density

• Gas particles move more freely

• Gases are heavier

• Gases have a lower temperature

Answer explanation

Diffusion occurs more rapidly in gases because gas particles move more freely compared to liquids. This increased freedom of movement allows gas particles to spread out and mix more quickly.

Which of the following factors increases the rate of diffusion in liquids?

• Decreasing the temperature

• Increasing the viscosity

• Stirring the liquid

• Reducing the surface area

Answer explanation

Stirring the liquid increases the rate of diffusion by promoting movement and mixing of particles, allowing them to spread more quickly. In contrast, decreasing temperature and increasing viscosity slow down diffusion.

What is the effect of increasing the concentration gradient on the rate of diffusion?

• It decreases the rate

• It has no effect

• It increases the rate

• It reverses the direction of diffusion

Answer explanation

Increasing the concentration gradient enhances the difference in concentration between two areas, which accelerates the movement of particles from high to low concentration, thus increasing the rate of diffusion.

Which of the following best describes diffusion?

• Movement of particles from low to high concentration

• Movement of particles from high to low concentration

• Movement of particles in a circular motion

• Movement of particles in a straight line

Answer explanation

Diffusion is the process where particles move from an area of high concentration to an area of low concentration, seeking to equalize their distribution. Thus, the correct description is 'Movement of particles from high to low concentration'.

How does the size of particles affect the rate of diffusion?

• Larger particles diffuse faster

• Smaller particles diffuse faster

• Particle size has no effect

• Larger particles stop diffusion

Answer explanation

Smaller particles diffuse faster because they have less mass and can move more easily through a medium. This increased mobility allows them to spread out more quickly compared to larger particles.

Which of the following is an example of diffusion in liquids?

• Smoke spreading in the air

• Ink spreading in water

• Metal rusting

• Ice forming on a pond

Answer explanation

Ink spreading in water is a clear example of diffusion in liquids, as the ink molecules move from an area of higher concentration to lower concentration, mixing evenly throughout the water.