Chemical Formulas, Reactions, and Water's Importance to Life

Vocabulary flashcards covering balanced chemical equations, molecular polarity, hydrogen bonding, and key physical properties of water from lecture slides.

Balanced Chemical Equation

An equation in which the same number of each type of atom occurs on both sides of the arrow.

Water Content in Organisms

The proportion of water in all living organisms, which is $70\text{--}90\text{\%}$.

Polar Covalent Bond in Water

A bond in which atoms do not share electrons equally; oxygen is more electronegative than hydrogen, causing electrons to spend more time around the oxygen nucleus so that the oxygen end becomes slightly negative and the hydrogens become slightly positive.

Hydrogen Bond

A bond formed when the slightly positive hydrogen of one water molecule is attracted to the slightly negative oxygen in another water molecule.

Solvency

The property of water that enables it to dissolve many substances due to polarity and hydrogen bonding, causing ionic compounds such as $\text{NaCl}$ to dissociate.

Hydrophilic

Describing molecules that are attracted to water.

Hydrophobic

Describing molecules that are not attracted to water.

Cohesion

The ability of water molecules to cling to each other due to hydrogen bonding.

Adhesion

The ability of water molecules to cling to other polar surfaces.

High Surface Tension

A property of water where molecules at the surface cling more tightly to each other than to the air above, mainly due to hydrogen bonding.

High Heat Capacity

A property of water where many hydrogen bonds allow water to absorb heat without greatly changing its temperature, causing water temperature to rise and fall slowly.

Heat of Vaporization

The property of water requiring a great deal of energy to break hydrogen bonds for evaporation, allowing heat to be dispelled as water evaporates.