Diffusion I: An Introduction

Diffusion is a process that only occurs in liquid substances.

• a.true
• b.false

When molecules diffuse through a substance, they appear to move down a concentration gradient. This is because the molecules are

• a.consciously moving to an area of the substance where there is more space.
• b.chemically interacting with the substance and changing it.
• c.randomly moving and colliding with one another.
• d.increasing the substance’s temperature, which causes the molecules to move.

The “random walk” of particles refers to

• a.the spontaneous movement of particles as they interact with their environment.
• b.the direct movement of particles from Point A to Point B.
• c.a property of matter unique to liquids.
• d.the average distance a particle travels between impacts with other particles.

A concentration gradient no longer exists when

• a.no more molecules are being added to the substance.
• b.all the molecules have reached equilibrium and stopped moving.
• c.the color of the substance has evened out.
• d.the added molecules have evenly spread throughout the substance and equilibrium has been reached.

Which of the following factors does NOT have a direct influence on the rate of diffusion?

• a.Molecule size
• b.Color
• c.Temperature
• d.Barriers in the substance

Which of the following examples would diffuse the FASTEST?

• a.Salt into salt water
• b.Salt water into salt water
• c.Salt into tap water
• d.Salt water into tap water

The diffusion rate differs between gases, liquids, and solids because the

• a.temperatures are different in each form.
• b.molecules are different sizes in each form.
• c.number of barriers in the molecule's way differ.
• d.distance molecules have to travel before colliding with another molecule differ.