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