What happens to the surface tension of water when a small amount of soap is adde

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Question: What happens to the surface tension of water when a small amount of soap is added?

Options:

Correct Answer: Decreases

Solution:

Adding soap decreases the surface tension of water because soap molecules disrupt the cohesive forces between water molecules.

What happens to the surface tension of water when a small amount of soap is added?

What happens to the surface tension of water when a small amount of soap is added?

Step 1: Understand what surface tension is. Surface tension is the force that makes the surface of water behave like a stretched elastic sheet.
Step 2: Know that water molecules are attracted to each other. This attraction creates strong cohesive forces that contribute to surface tension.
Step 3: When soap is added to water, soap molecules mix with the water. Soap molecules have a special structure that allows them to interact with both water and air.
Step 4: The soap molecules disrupt the cohesive forces between the water molecules. This means that the water molecules are not as strongly attracted to each other anymore.
Step 5: Because the cohesive forces are weaker, the surface tension of the water decreases. This makes it easier for things to float on the surface or for bubbles to form.

Surface Tension – The cohesive forces between liquid molecules at the surface that create a 'skin' effect.
Effect of Surfactants – Substances like soap that reduce surface tension by disrupting intermolecular forces.