Ch.2 Properties of Water

Covalent Bond

A covalent bond is a chemical bond that involves the sharing of electron pairs between atoms. These electron pairs are known as shared pairs or bonding pairs and the stable balance of attractive and repulsive forces between atoms when they share electrons is known as covalent bonding.

Hydrogen Bond

A hydrogen bond is the electrostatic attraction between polar molecules that occurs when a hydrogen (H) atom bound to a highly electronegative atom such as nitrogen (N), oxygen (O) or fluorine (F) experiences attraction to some other nearby highly electronegative atom.

Ionic Bond

Ionic bonding is a type of chemical bond that involves the electrostatic attraction between oppositely charged ions, and is the primary interaction occurring in ionic compounds. The ions are atoms that have lost one or more electrons (known as cations) and atoms that have gained one or more electrons (known as anions).

Water the universal solvent

Many substances dissolve in it, waters solvency has to do with the polarity and hydrogen bonds of its water molecules. The positive ends of the salt (sodium) are attracted to the negative ends of the water molecules (hydrogen), and vice versa with the negative oxygen and positive chlorine. This causes the sodium and chlorine to disconnect from each other breaking their ionic bond.

The density of water is based upon it's temperature

The configuration of hydrogen bonds causes it to expand when it freezes. This expansion causes frozen water to have a lower density than liquid water.

Water molecules are cohesive and adhesive

The hydrogen bonds of water cause the water molecules to stick together (cohesion). Polar bonds also give water molecules an adhesive bond, the ability to cling to other polar surfaces.

Polarity of water

The two hydrogen atoms and one oxygen atom within water molecules (H 2O) form polar covalent bonds. While there is no net charge to a water molecule, the polarity of water creates a slightly positive charge on hydrogen and a slightly negative charge on oxygen, contributing to water's properties of attraction.

Water has a high heat capacity

This means that the many hydrogen bonds that link water molecules let water absorb a large amount of heat without changing it's chemical state.

Water exists on Earth in all three states

Water appears on Earth NATURALLY, in solid form (ice), liquid form (water), and gas form (steam).

Unique Properties Of Water

Water is a universal solvent, it exists in nature as a solid, liquid, and gas, the density of ice is less than liquid water, has a high surface tension, has a high heat capacity, and does cohesion and adhesion

Water has a high level of surface tension

Water molecules are more attracted to each other than the air above, so then the water molecules cling tightly to each other.