Biology and Thermodynamics Lecture Vocabulary

Vocabulary flashcards covering foundational chemistry, properties of water, pH buffers, energy states, and the laws of thermodynamics based on the lecture notes.

Element

Any pure substance that cannot be broken down into any other substance by ordinary chemical means.

Protons

Positively charged subatomic particles that determine the identity of an element and balance the number of electrons in a neutral atom.

Neutrons

Subatomic particles that act as glue to hold protons together in the atomic nucleus against repelling positive charges.

Isotope

Atoms of the same element with varying numbers of neutrons that are chemically identical to the common atom but may be radioactive.

Radium ($RA$)

A highly radioactive element isolated by Marie Curie that chemically resembles calcium and gets incorporated into bone tissue.

Covalent Bond

A strong chemical bond formed when atoms link together by sharing electrons within a molecule.

Ionic Bond

A strong chemical bond formed between cations and anions that can be dissolved in water or polar solvents.

Heat Capacity

A property of water requiring five times more heat to raise its temperature by $1\,^{\circ}\text{C}$ compared to metals like aluminum.

High Heat of Vaporization

A property of water requiring $540\,\text{cals/gram}$ of energy to undergo a phase transition from liquid to gas without changing temperature.

Cohesion

The property of water molecules sticking to other water molecules via polar attraction.

Adhesion

The property of water molecules sticking to other polar non-water molecules.

pH

A logarithmic scale measuring acidity or basicity, defined mathematically as $pH = -\log([H^+])$.

Mole

A unit representing $6.022 \times 10^{23}$ particles of a substance, commonly expressed in concentrations of moles per liter ($\text{mol/L}$).

Acid

Any substance that dissociates in water to increase the $H^+$ ion concentration, lowering the pH below $7$.

Base

Any substance that dissolves in water to decrease the $H^+$ ion concentration or increase $OH^-$ ions, raising the pH above $7$.

Buffer

A solution of a weak acid and its conjugate weak base in equal molar amounts that resists changes in pH.

Carbonic Acid

A weak acid ($H_2CO_3$) formed by the reaction of carbon dioxide ($CO_2$) and water ($H_2O$) that dissociates into $H^+$ and bicarbonate ($HCO_3^-$) to regulate blood pH.

Carbon-14 Dating

A radiometric dating method based on the exponential decay curve of carbon-14 relative to carbon-12, with a half-life of $5,735\,\text{years}$.

Energy

The incorporeal capacity or ability to do work.

Kinetic Energy

The state of energy associated with motion.

Potential Energy

Stored energy that can be converted into kinetic energy.

Thermodynamics

The study of energy and heat changes across various physical and chemical processes.

First Law of Thermodynamics

A physical law stating that the total amount of energy in a closed system remains constant and cannot be created or destroyed, only transformed.

Second Law of Thermodynamics

A physical law stating that the total disorder or entropy ($S$) in the universe is constantly increasing.

Entropy

A quantitative measure of disorder or randomness in a system, mathematically expressed as $S = k \ln(W)$.

Endergonic Reaction

A chemical reaction that requires an input of energy because the products contain more energy than the reactants.

Exergonic Reaction

A spontaneous chemical reaction that releases energy as heat, resulting in products with less energy than the reactants.

Activation Energy

The initial input of energy required to trigger a chemical reaction and transform reactants into products.