8.6C Adhesion, Cohesion, and Surface Tension

Surface tension is the property of water in which...

• water molecules at the surface tend to stick together.

• water spills easily.

• water tends to be see-through.

Answer explanation

Surface tension occurs because water molecules at the surface are attracted to each other more strongly than to the air above, causing them to stick together. This is why the correct answer is that water molecules at the surface tend to stick together.

Refer to the picture of water sticking to a leaf; this is occurring because of:

• Adhesion

• Cohesion

Answer explanation

Water sticks to the leaf due to adhesion, which is the attraction between different substances, in this case, water molecules and the leaf surface. Cohesion refers to the attraction between water molecules themselves.

Describe COHESION.

• Water molecules attracted to other substances.

• Water molecules climbing upwards against the force of gravity.

• Water molecules dissolving many substances because of its polarity.

• Water molecules attracted to other water molecules.

Answer explanation

Cohesion refers to the attraction between water molecules themselves. This property allows water to form droplets and creates surface tension, making 'Water molecules attracted to other water molecules' the correct choice.

What two elements make up water?

• Helium and oxygen

• Hydrogen and oxygen

• helium and carbon

• oxygen and carbon

Answer explanation

Water is composed of two elements: hydrogen and oxygen. The chemical formula for water is H2O, indicating that each molecule contains two hydrogen atoms bonded to one oxygen atom.

Tags

NGSS.MS-PS1-1

What word describes when water is attracted to other substances?

• cohesion

• adhesion

• capillary action

• surface tension

Answer explanation

The correct answer is adhesion, which describes the attraction between water molecules and other substances. Cohesion refers to water's attraction to itself, while capillary action and surface tension are related concepts but not the definition asked.

tendency of molecules of the same kind to stick to one another

• cohesion

• adhesion

• solution

• polar molecule

Answer explanation

The tendency of molecules of the same kind to stick to one another is called cohesion. This property is crucial in understanding how liquids behave, as it allows them to form droplets and maintain their shape.

Water droplets take a spherical shape (as pictured) because of ____________

• adhesion

• cohesion

• capillary action

• solubility

Answer explanation

Water droplets take a spherical shape due to cohesion, which is the attraction between water molecules. This cohesive force pulls the molecules together, minimizing surface area and forming a sphere.

Water beads up on the surface of a penny because of this property.

• Adhesion

• High Surface Tension

• Universal Solvent

• Changes in Density

Answer explanation

Water beads up on a penny due to high surface tension, which is the cohesive force between water molecules. This property causes the water to minimize its surface area, forming droplets instead of spreading out.

Which characteristic of water will allow a paperclip to remain floating on water when the paperclip is gently placed on top of the water?

• adhesion

• surface tension

• solvent properties

• nonpolar

Answer explanation

The paperclip floats due to surface tension, a property of water that creates a 'skin' on the surface, allowing it to support light objects. This characteristic prevents the paperclip from sinking when placed gently.

Water's ability to stick to glass is

• adhesion

• cohesion

• surface tention

• capillary action

Answer explanation

Water's ability to stick to glass is due to adhesion, which is the attraction between different substances, such as water molecules and glass. Cohesion refers to the attraction between similar molecules, while surface tension and capillary action involve different concepts.