Understanding Emulsions and Emulsifying Agents

What is an emulsion as explained using milk?

• A dispersion of one liquid in another

• A mixture of two solids

• A solution of a solid in a liquid

• A gas dissolved in a liquid

What happens when you shake oil and water together?

• They dissolve completely

• They form a temporary emulsion

• They remain separate

• They form a permanent emulsion

How can you make a permanent emulsion?

• By heating the mixture

• By adding more water

• By cooling the mixture

• By adding soap

What role does the hydrophobic part of a soap molecule play?

• It evaporates

• It dissolves in water

• It reacts with air

• It dissolves in oil

Why do oil droplets in an emulsion not combine?

• Because they are too light

• Because they are too heavy

• Because they are charged and repel each other

• Because they are too small

What is the charge on the surface of oil droplets in an emulsion?

• Neutral

• Positive

• Variable

• Negative

What is the role of the hydrophilic part of a soap molecule?

• It reacts with air

• It evaporates

• It dissolves in water

• It dissolves in oil

How does soap help in cleaning clothes?

• By forming a permanent emulsion with dirt

• By changing the color of the fabric

• By dissolving the fabric

• By evaporating the water

What happens to the oil layer when soap is added to an oil-water mixture?

• It evaporates

• It thickens

• It separates immediately

• It remains mixed

Why is soap considered an emulsifying agent?

• Because it dissolves in both oil and water

• Because it prevents oil and water from separating

• Because it evaporates quickly

• Because it changes the color of the mixture