Diffusion and Effusion

According to the kinetic molecular theory, the volume actually occupied by the molecules of a gas is negligibly small; the vast majority of the volume of the gas is empty space through which the gas molecules are moving.

• True

• False

The walls of the capillaries and alveoli help in gas exchange through a process called........................

• effusion

• osmosis

• diffusion

Alveoli are designed with thin walls to make diffusion fast because

Red blood cells squeeze along the capillaries around them.

• True

• False

Alveoli are designed with thin walls to make diffusion fast because..................................

• it has large surface area.

• it has a small surface area.

It is a type of passive transport which involves the movement of substances from a high concentration area to a low concentration area.

• effusion

• diffusion

• concentration gradient

Which best describes which directions molecules move during diffusion?

• from an area of equilibrium to an area of high concentration

• from an area of equilibrium to an area of low concentration

• from an area of low concentration to an area of high concentration

• from an area of high concentration to an area of low concentration

What is the process by which water diffuses across a selectively permeable membrane?

• active  transport

• osmosis

• simple diffusion

• facilitated diffusion

Which of the following best describes effusion?

• The movement of particles from high to low concentration through a membrane

• The escape of gas particles through a tiny hole into a vacuum

• The mixing of gas particles in a container

• The movement of water across a selectively permeable membrane

According to Graham's law, the rate of effusion of a gas is inversely proportional to the square root of its:

• Density

• Molar mass

• Volume

• Temperature

Which experiment can demonstrate the process of diffusion?

• Observing the spreading of a drop of ink in water

• Measuring the rate of gas escaping through a pinhole

• Heating a liquid to observe boiling

• Mixing oil and water