Chemistry and Water - Vocabulary Flashcards

Vocabulary flashcards covering key concepts from Chemistry and Water lecture notes.

Atom

The fundamental unit of matter.

Nucleus

The center of an atom that contains protons and neutrons.

Proton

A positively charged subatomic particle located in the nucleus.

Neutron

An electrically neutral subatomic particle located in the nucleus.

Electron

A negatively charged subatomic particle that orbits the nucleus; its weight is negligible.

Element

A substance that cannot be reduced to simpler substances by chemical means.

Atomic Number

The number of protons in the nucleus; defines the element.

Ion

An atom with a net electric charge due to gain or loss of electrons.

Cation

A positively charged ion formed when an atom loses electrons.

Anion

A negatively charged ion formed when an atom gains electrons.

Isotope

Forms of an element with different numbers of neutrons.

Radioactive Decay

Unstable isotopes decay into more stable ones by emitting radiation.

Atomic Mass Unit (amu)

A unit of mass used to express atomic and molecular weights.

Hydrogen Isotopes (Deuterium, Tritium)

Variants of hydrogen with different numbers of neutrons.

Major Elements in the Human Body

O, C, H, N; collectively ~96% of body mass.

Covalent Bond

A chemical bond formed when atoms share one or more electrons.

Polar Covalent Bond

A covalent bond where shared electrons are not equally shared due to electronegativity differences.

Nonpolar Covalent Bond

A covalent bond where electrons are shared equally between atoms.

Ionic Bond

A bond formed by electrostatic attraction between oppositely charged ions.

Electronegativity

An atom’s ability to attract electrons in a chemical bond.

Molecule

A group of atoms bonded covalently in a defined arrangement.

Water Molecule (H2O)

A molecule composed of two hydrogen atoms covalently bonded to one oxygen atom.

Hydrogen Bond

A weak attraction between opposite poles of polar molecules, especially involving H and O or N.

Hydrophobic

An interaction with water-averse compounds (nonpolar hydrocarbons).

Hydrophilic

A compound that interacts with water (polar or charged).

Solution

A homogeneous mixture of solute dissolved in solvent.

Solvent

The substance that dissolves another substance.

Solute

The substance dissolved in a solvent.

Aqueous Solution

A solution where the solvent is water.

Cohesion

Attraction between like molecules (e.g., water–water).

Adhesion

Attraction between water molecules and other polar substances.

Surface Tension

A measure of the cohesive forces at the surface of a liquid.

Ice Density vs. Liquid Water

Ice is less dense than liquid water, so it floats; caused by hydrogen bonding in ice.

Water as a Solvent

Water can dissolve many substances; it has high solvent power.

pH

A measure of hydrogen ion concentration in an aqueous solution; scale 0–14 and logarithmic.

Acid

A substance that yields hydrogen ions (H+) in water.

Base

A substance that accepts hydrogen ions, reducing acidity.

Neutral pH

A pH of 7, considered neutral in pure water.

Neutralization

An acid–base reaction that forms water and a salt.

Biological pH Preference

Living systems generally function best near neutral pH, though some processes require different values.