7b Quiz

On which surface the water drop will be the most flattened?

• steel

• on waxed sheet of paper

• on piece of plastic

The lower the adhesion forces between the liquid and the substrate, the more flattened the water drop is.

• true

• false

In which picture the adhesion forces between water molecules and the substrate are the smallest?

• A

• B

• C

Where detergent is added, the surface tension decreases.

• true

• false

When we are dealing with surface tension?

• during washing dishes

• while washing clothes

• while frying

• while vacuuming

What are cohesive forces?

• they work when molecules of different substances interact with each other

• the forces work when molecules of the same substance interact

• they work when for example a glass falls to the ground

• they work when the surface of a liquid curves against a wall

What is adhesion force?

• the forces work when molecules of different substances interact with each other

• they work when molecules of the same substance interact

• they work when for example a glass falls to the ground

• they work when the surface of a liquid curves against a wall

What is the meniscus?

• it is the result of intermolecular actions

• it is the result of interatomic actions

• it is the curvature of the liquid at the vessel wall

• meniscus is the curvature of the liquid surface at the vessel wall

Does the toothpick change its position after adding detergent?

• it doesn't change position

• it drownes

• the toothpick gently lowers

What strongly affects surface tension?

• temperature

• the pressure

• the moon's position

• the sun's gravity