Diffusion

Question 1

Someone opens a bottle of perfume in one corner of a still room. Soon it is smelled everywhere. Why?

• A. Perfume particles are pulled by gravity
• B. Air particles stop moving
• C. Perfume particles diffuse from high to low concentration
• D. The perfume becomes a solid

Question 2

Diffusion: which statement is NOT true?

• A. A larger surface area speeds up diffusion.
• B. Diffusion happens in gases and liquids.
• C. Diffusion stops completely when the room is cold.
• D. Diffusion does not need energy from respiration.

Question 3

Agar cubes containing indicator were put into acid. Time for the whole cube to change colour: 1 cm cube 8 min, 2 cm cube 16 min, 3 cm cube 24 min. Which cube's centre was reached fastest by the acid?

• A. the 1 cm cube
• B. the 2 cm cube
• C. the 3 cm cube

Question 4

Oxygen moves from the alveoli into the blood. Why?

• A. The heart pushes air in
• B. There is more oxygen in the alveoli than in the blood
• C. Blood pulls oxygen like a magnet
• D. Oxygen is heavier than blood

Question 5

Diffusion: which statement is NOT true?

• A. A steeper concentration gradient gives faster diffusion.
• B. Diffusion happens in gases and liquids.
• C. Particles stop moving once they are evenly spread.
• D. Diffusion does not need energy from respiration.

Question 6

Purple dye spread 12 mm through a block of jelly in 3 hours. What was the mean rate of diffusion, in mm per hour?

Answer mm/h

Question 7

Someone opens a bottle of perfume in one corner of a still room. Soon it is smelled everywhere. Why?

• A. The perfume becomes a solid
• B. Perfume particles are pulled by gravity
• C. Air particles stop moving
• D. Perfume particles diffuse from high to low concentration

Question 8

Diffusion: which statement is NOT true?

• A. Diffusion moves particles from low to high concentration.
• B. A steeper concentration gradient gives faster diffusion.
• C. Diffusion does not need energy from respiration.
• D. Diffusion happens in gases and liquids.

Question 9

Purple dye spread 9 mm through a block of jelly in 2 hours. What was the mean rate of diffusion, in mm per hour?

Answer mm/h

Question 10

Oxygen moves from the alveoli into the blood. Why?

• A. The heart pushes air in
• B. Blood pulls oxygen like a magnet
• C. There is more oxygen in the alveoli than in the blood
• D. Oxygen is heavier than blood

Question 11

Diffusion: which statement is NOT true?

• A. A larger surface area speeds up diffusion.
• B. Diffusion happens in gases and liquids.
• C. Particles stop moving once they are evenly spread.
• D. Diffusion does not need energy from respiration.

Question 12

Agar cubes containing indicator were put into acid. Time for the whole cube to change colour: 1 cm cube 6 min, 2 cm cube 12 min, 3 cm cube 24 min. Which cube's centre was reached fastest by the acid?

• A. the 1 cm cube
• B. the 2 cm cube
• C. the 3 cm cube

Question 13

Carbon dioxide made by respiring cells moves into the blood. Which way is the gradient?

• A. the same on both sides
• B. higher in the blood, lower in the cells
• C. higher in the cells, lower in the blood
• D. there is no carbon dioxide in cells

Question 14

Diffusion: which statement is NOT true?

• A. Diffusion moves particles from low to high concentration.
• B. Diffusion does not need energy from respiration.
• C. Diffusion happens in gases and liquids.
• D. A steeper concentration gradient gives faster diffusion.

Question 15

Purple dye spread 15 mm through a block of jelly in 3 hours. What was the mean rate of diffusion, in mm per hour?

Answer mm/h

Question 16

Which change would make diffusion faster?

• A. a higher temperature
• B. a lower temperature
• C. a thicker membrane
• D. a smaller surface area