Water Basics

Water _____ -boils at 100°C -cools very quickly -is made of helium and oxygen -is slightly acidic at the oxygen end

boils at 100°C

The oxygen side of a water molecule is _____.

slightly negative

adhesion

water's attraction to other substances

cohesion

water's attraction to other water molecules

Cohesion describes water's _____.

Since opposite charges attract, water molecules tend to attract each other and stick close together. This property is called cohesion.

Which of the following statements is true? -Water is easily polluted because it can dissolve harmful chemicals. -When water freezes, it contracts and becomes more dense. -Thermal pollution happens when cold water is released into an ecosystem. -Adhesion describes a water molecule's attraction to another water molecule.

Water is easily polluted because it can dissolve harmful chemicals.

surface tension

cohesion of water molecules at the surface of a body of water

solvent

substance in which another substance is dissolved

compound

two or more elements joined together to create a new substance

The "hardness" of water describes _____.

Most water contains some level of dissolved calcium and magnesium. The amount determines its "hardness."

Surface tension _____. -causes water to spread out -is the ability of water to dissolve a substance -creates a thin, elastic layer of hydrogen atoms -is caused by cohesion between water molecules on the surface

is caused by cohesion between water molecules on the surface

Ice floats in water because it _____.

is less dense

polarity

molecular condition in which one end has a slightly positive charge and the other a slightly negative charge