Chemical Basis of Life - Lecture Flashcards

Vocabulary flashcards generated from the chapter lecture notes covering atoms, chemical bonds, molecular structures, and water chemistry.

Matter

Anything that has mass and occupies space.

Mass

The amount of material in an object related to the type and amount of the atoms present; it does not change based on location.

Weight

A measurement completely based on gravitational pull.

Atom

The smallest functional unit of matter that cannot be broken down by ordinary chemical means.

Protons

Positively charged subatomic particles located in the nucleus of an atom.

Neutrons

Electrically neutral subatomic particles located in the nucleus of an atom.

Electrons

Negatively charged subatomic particles that orbit the nucleus.

s Orbitals

Spherical orbitals that can hold up to $2$ electrons.

p Orbitals

Propeller or dumbbell-shaped orbitals that can hold up to $2$ electrons each.

Valence Electrons

Electrons in the outer shell that are available to combine with other atoms.

Atomic Number

The number of protons in an atom, which distinguishes one element from another and equals the number of electrons in a neutral atom.

Atomic Mass

The mass of an atom calculated by adding the total number of protons and neutrons.

Dalton (Da)

A unit of measurement for atomic mass, also known as an atomic mass unit ($\text{AMU}$), where $1\text{ Da}$ equals $1/12$ the mass of a carbon atom.

Mole

A measurement where $1\text{ mole}$ of any element contains $6.022 \times 10^{23}$ atoms.

Isotopes

Forms of an element that differ in their number of neutrons, resulting in different masses.

Radioisotopes

Unstable isotopes that emit radiation as they decay, useful in medical treatments and imaging.

Molecule

A particle formed when two or more atoms are bonded together.

Compound

Any molecule composed of two or more different elements.

Covalent Bond

A strong chemical bond formed when atoms share pairs of electrons to fill their valence shells.

Octet Rule

The rule stating that atoms are most stable when their outer electron shell is filled, which for many atoms requires $8$ electrons.

Electronegativity

The ability of an atom to attract an electron.

Polar Covalent Bond

A covalent bond between atoms with different electronegativities, causing electrons to be shared unequally.

Nonpolar Covalent Bond

A covalent bond formed between atoms with similar electronegativities, resulting in equal sharing of electrons and no net charge difference.

Polarity

A difference in electric charge across a molecule created by the unequal distribution of electrons.

Hydrogen Bond

A weak individual attraction formed when a hydrogen atom in a polar molecule is attracted to an electronegative atom in another molecule.

Van der Waals Dispersion Forces

Weak, fleeting electrical attractions between nearby molecules caused by the random location of electrons within orbitals.

Ion

An atom or molecule that has gained or lost one or more electrons, giving it a net electrical charge.

Cation

An ion with a net positive charge.

Anion

An ion with a net negative charge.

Ionic Bond

A chemical bond formed when electrons are transferred from one atom to another, resulting in an electrostatic attraction between a cation and an anion.

Free Radicals

Highly reactive atoms or molecules with a single unpaired electron in their outer shell that can steal electrons from other molecules.

Antioxidants

Protective compounds that donate electrons to free radicals without becoming highly reactive themselves.

Aqueous Solution

A solution in which water serves as the solvent.

Solute

The substance that is dissolved in a liquid solution.

Solvent

The liquid substance in which a solute is dissolved.

Hydrophilic

Molecules containing polar covalent bonds or ionic charges that readily dissolve in water.

Hydrophobic

Nonpolar molecules that do not dissolve in water.

Amphipathic Molecules

Molecules containing both polar and nonpolar regions that assemble into structures such as micelles in water.

Concentration

The amount of a solute dissolved in a specific unit volume of solution.

Molarity

The number of moles of a solute dissolved in $1\text{ L}$ of solution.

Specific Heat

The amount of heat energy required to raise the temperature of $1\text{ g}$ of a substance by $1\,^\circ\text{C}$.

Heat of Vaporization

The amount of energy needed to convert a liquid into a gas (boil water).

Heat of Fusion

The amount of energy needed to melt ice into liquid water.

Colligative Properties

Properties of a solution that depend strictly on the total number of dissolved solute particles rather than the specific type of solute.

Hydrolysis

A chemical reaction in which water molecules are used to break other chemical bonds apart.

Acids

Molecules that release hydrogen ions ($\text{H}^+$) in solution, lowering the pH.

Bases

Substances that lower the hydrogen ion ($\text{H}^+$) concentration in a solution by binding hydrogen ions or releasing hydroxide ions ($\text{OH}^-$).

Buffers

Substances containing acid-base pairs that minimize changes in $\text{H}^+$ and $\text{OH}^-$ concentrations to maintain a constant pH.