Flashcards- Ch 3 Properties of Water

Front

Describe the structure of water molecules.

Back

Water molecules have a polar structure with partial negative charges on oxygen and partial positive charges on hydrogen. The oxygen atom should also show two unshared electron pairs (this is not shown in this image).

Front

Surface tension of water

Back

Surface tension in water allows it to form droplets and create ripples, and enables insects to walk on water without sinking. This is due to the cohesive forces between water molecules being stronger at the surface.

Front

number of hydrogen bonds each water molecule can form

Back

Each water molecule can form a maximum of 4 hydrogen bonds with neighboring water molecules due to its polarity (1 from each of the 2 hydrogens and 1 from each of the 2 unshared electron pairs)

Front

Compounds that are hydrophilic

Back

Hydrophilic compounds are "water loving" and are soluble in water.
Ex: polar compounds such as sugars; ionic compounds such as salts

Front

Ionic compounds and water

Back

Charged regions of polar water molecules have an electrical attraction to charged ions.

Front

Polar compounds and water

Back

Charged regions of polar water molecules are attracted to oppositely charged regions of other polar molecules (e.g., glucose).

Front

"Like dissolves like"

Back

This phrase means that substances with similar properties (e.g., polarity) tend to dissolve in each other.

Polar substances have charge so they can dissolve other substances that also have charge, such as other polar compounds or ionic compounds. Ex: water can dissolve sugars or salts but it cannot dissolve oil since oil is nonpolar.

Nonpolar substances lack charge so they can dissolve other nonpolar substances. Ex: vegetable oil can be used to remove tar skin, such as your feet if you step on it at the beach.

Front

Hydrophobic compounds

Back

Hydrophobic compounds are "water fearing" and insoluble in water. Examples include certain plastics and oils.

Front

Nonpolar compounds and water

Back

Nonpolar compounds have a symmetric distribution in charge or are composed of nonpolar bonds. They are not attracted to or soluable in water. Example: oil cannot be dissolved in water

Front

Water is a versatile solvent due to its polarity.

Back

Water's polarity allows it to form shells around charged or other polar molecules. It can dissolve a lot of different substances and is often called "the universal solvent" or "the solvent of life".