Introduction to Water and Chemical Bonds Flashcards

Vocabulary flashcards reviewing chemical bonds, polar molecules, and the unique physical and chemical properties of water based on the lecture notes.

Hydrogen bond

A weak interaction occurring between a partially positive hydrogen atom in one polar molecule and a partially negative atom in another molecule.

Van der Waals interactions

Weak attractions between molecules that help stabilize the three-dimensional structures of proteins and other large biological molecules.

Hydrophilic interaction

An interaction between polar molecules, such as a water molecule interacting with another polar molecule ("water-loving").

Kinetic energy

The energy of motion in molecules, which increases as heat is introduced into a system, causing water molecules to move faster and break hydrogen bonds.

Specific heat capacity

The amount of heat $1\,\text{gram}$ of a substance must absorb or lose to change its temperature by $1\,^\circ\text{C}$. For water, this is $1\,\text{calorie/g} \cdot ^\circ\text{C}$ or $4.184\,\text{joules/g} \cdot ^\circ\text{C}$.

Heat of vaporization

The amount of energy required to change $1\,\text{gram}$ of a liquid substance to a gas, which equals $586\,\text{calories/gram}$ for water at its boiling point of $100\,^\circ\text{C}$.

Liquid-air interface

The boundary or point where liquid water meets the air, where surface water molecules undergo vaporization or evaporation.

Evaporation

The process occurring below water's boiling point ($100\,^\circ\text{C}$) where individual surface water molecules acquire enough kinetic energy from surrounding molecules to escape into the air as gas.

Cohesion

The attraction between water molecules held together by hydrogen bonding at the liquid-gas or liquid-air interface.

Surface tension

The capacity of a substance to withstand rupture when placed under tension or stress, created in water by cohesive hydrogen bonding at the liquid-gas interface.

Adhesion

The attraction between water molecules and other types of molecules, such as the charged surface inside a glass capillary tube.

Capillary action

The movement of water climbing up a thin tube driven by adhesive attraction between water molecules and the charged walls of the tube.

Solvent

A substance capable of dissolving other polar molecules and ionic compounds, acting as the dissolving agent in a solution.

Solution

A liquid that is a completely homogeneous mixture composed of substances existing in only one state of matter.

Solute

The substance that is dissolved inside a solvent to form a homogeneous solution.

Aqueous solution

A solution in which water acts as the solvent.

Hydration shell

A surrounding sphere of water molecules oriented around a dissolved ion or polar molecule due to charge interactions and hydrogen bonding.