The Chemistry of Soap: It's a Wash!

Why wash with soap? Because water alone is pretty ____________.

• oily

• membrane

• superficial

• wetter

Water molecules are attracted to each other in a ‘happy clique’ except for molecules at the ______________________.

• surface

• grease

• micelles

• float

The parts of water at the surface are exposed to ______________.

• dirty

• beads

• animal

• air

Water molecules at the surface shrink ____________ from the air and pull closer to the water molecules next to and ______________ it.

• fatty; oily

• away; below

• float; break

• quickly; loosen

The outward and downward pulling ________________ the exposed top part of the surface, forming a thin __________________ like an invisible ____________.

• oily; natural; micelles

• quickly; surface; synthetic

• itself; hydrophilic; hydrophobic

• stretches; membrane; skin

The molecules stick to each other and it is hard to pull them apart. We say that water has a __________________surface tension.

• high

• float

• air

• grease

Surface tension explains why a paper clip can _____________on water, certain insects can _________ on water, and water ______________ up on a surface.

• likes; opposite; water

• quickly; below; break

• float; walk; beads

• air; surface; bases

Water tends to huddle up together but this is the _____________________ (opposite) of what we need it to do to clean.

• quickly

• opposite

• chemically

• high

We need water to spread ________________over a ________________ surface to start to _______________the dirt.

• membrane; stretches; skin

• air; fatty; hydrophilic

• oily; greasy; high

• quickly; dirty; loosen

There is a difference between soaps and detergents. Soaps are made from _____________________ ingredients like __________________ fats and oils and lye. Detergents are _____________________ or manmade.

• natural; animal; synthetic

• air; oily; grease

• high; hydrophobic; quickly

• oil; surface; likes