Chemistry of Life - Elements, H2O, and Hydrogen Bonding

Vocabulary flashcards covering key concepts from the lecture notes on elements, water (H2O), and hydrogen bonding.

92 essential elements

There are 92 elements essential for organisms to live and reproduce.

96% of living matter

These essential elements make up about 96% of living matter.

Chemical bonds

Attraction between two atoms resulting from sharing or transferring valence electrons.

Electronegativity

Ability of an atom to attract electrons to itself.

Electronegativity difference

The difference in electronegativities between two atoms determines what type of bond will form.

Non-polar covalent bond

Electrons are shared equally between atoms, resulting in no partial charges.

Polar covalent bond

Electrons are shared unequally, creating partial charges.

Ionic bond

Electrons are transferred from one atom to another, forming cations and anions.

Covalent bond

Sharing of electrons between atoms.

Hydrogen bond

A partially positive hydrogen atom in one molecule is attracted to a highly electronegative atom (O, N, F) in another molecule (example: water).

Water polarity

Water is a polar molecule with partial charges, enabling hydrogen bonding.

Cohesion

Attraction between molecules of the same type, due to hydrogen bonding; helps water transfer in plants.

Adhesion

Attraction between molecules of different types; water to cell walls helps water rise in plants.

Surface tension

Measure of how difficult it is to stretch or break the surface of a liquid; higher in water due to cohesion.

Capillary action

Upward movement of water due to cohesion, adhesion, and surface tension; occurs when adhesion is greater than cohesion.

High specific heat

The amount of energy needed to raise the temperature of 1 g of a substance by 1°C; water has a very high value, moderating temperature.

High heat of vaporization

The heat required to convert liquid water to a gas; evaporation cools surfaces.

Floating ice

Ice is less dense than liquid water; hydrogen bonds create an open lattice, allowing ice to float and support aquatic life.

Solvent

Water dissolves many substances; the dissolving agent in a solution.

Solute

The substance being dissolved.

Solution

A homogeneous mixture of two or more substances.

Like dissolves like

Substances with similar intermolecular forces dissolve in each other.

Water as solvent for sugars and proteins

Water can form hydrogen bonds with sugar and protein to dissolve them.