Significance of Water and Elements of Life

Vocabulary flashcards covering the chemical properties of water, chemical reactions involving water, pH buffers, and the elements of life.

Polar molecule

A covalent compound that shares its electrons unequally between its atoms, resulting in a slightly negative oxygen atom and slightly positive hydrogen atoms.

Universal solvent

A term for water due to its ability to dissolve a large number and variety of materials, including both polar and ionic, organic and inorganic compounds.

Hydrogen bond

An attraction between a positively charged hydrogen atom and a negatively charged atom, which is not a true chemical bond.

Cohesion

The property of water molecules sticking to one another as they form hydrogen bonds with itself.

Adhesion

The property of water molecules sticking to other surfaces, such as plant xylem tubes.

Surface Tension

The ability of water to support small objects caused by hydrogen bonds between neighboring molecules forming a film at the surface.

Transpiration

The movement of water upward against gravity in plant xylem tubes, facilitated by cohesion and adhesion.

Hydrolysis

A chemical process in which compounds are cleaved into parts by the addition of a molecule of water, where one fragment gains $H^+$ and the other group collects $OH^-$.

Condensation

Also called dehydration synthesis, the reverse of hydrolysis where 2 molecules combine to form a larger molecule with the removal of a water molecule.

Dissociation

A usually reversible process facilitated in water where molecules or ionic compounds are separated into smaller particles.

Buffer

A chemical that resists changes in pH, which helps organisms maintain an optimal pH for enzyme activity.

Atoms

The basic building blocks of matter, where all atoms of a given element have the same number of protons and electrons.

Organic compounds

Compounds containing carbon, hydrogen, and oxygen, such as $CH_4$ and $C_6H_{12}O_6$.

Inorganic compounds

Compounds that do not contain carbon and hydrogen together, such as $H_2O$, $NaCl$, and $CO_2$.

Oxygen (O)

The most abundant element in living things, making up $65\%$ of their composition.

Carbon (C)

An element making up $18.5\%$ of living things that is unique due to having 4 valence electrons and the ability to form 4 covalent bonds.

Hydrogen (H)

An element that makes up $9.5\%$ of the elemental composition of living things.

Nitrogen (N)

An element that makes up $3.3\%$ of the elemental composition of living things.

Sulfur (S)

Element 16, which is found in some amino acids and proteins.

Phosphorus (P)

Element 15, which is needed to build and repair DNA, and is found in ATP, DNA/RNA, and cell membranes.

Calcium (Ca)

Element 20, which is needed for nerve, bone, and muscle cell functioning.

Iron (Fe)

Element 26, which is found in hemoglobin and is essential for oxygen transport in blood.

Sodium (Na)

An element needed for nerve and muscle cell function.