Question

What effect did the soap have on the penny in the penny drop experiment?

A) Increased cohesion between water molecules.

B) Decreased the capillary action between water molecules and the penny.

C) Increased adhesion and allowed fewer water molecules to stick to the penny.

D) Reduced cohesion between water molecules.

Answer 1

Soap D) reduces the cohesion between water molecules by disrupting hydrogen bonds, causing a decrease in water's surface tension and leading to fewer droplets sticking to the penny.

Step-by-step explanation:

The effect soap had on the penny in the penny drop experiment relates to the surface tension of water. The correct effect that the soap has on the penny in the penny drop experiment is D) Reduced cohesion between water molecules. By adding soap (a surfactant) to water, it disrupts the hydrogen bonding between water molecules, resulting in a decrease in surface tension. Soap molecules arrange themselves at the surface of water with their hydrophobic tails sticking out, reducing the cohesive forces between water molecules. This decreases the water's ability to form drops and allows the water to spread out more easily, which is why fewer water droplets would stick to the penny.