Hydrogen Bonding and the Properties of Water

These flashcards cover the chemical properties of water, including hydrogen bonding, temperature moderation, density, solvent versatility, and the pH scale.

Water molecules are __________, meaning the oxygen region has a partial negative charge and the hydrogen region has a partial positive charge.

polar molecules

The attractions between the opposite partial charges of neighboring water molecules are called __________.

hydrogen bonds

The four emergent properties of water that contribute to Earth's suitability for life are cohesive behavior, ability to moderate temperature, __________, and versatility as a solvent.

expansion upon freezing

The phenomenon where water molecules stay close together due to multiple hydrogen bonds is known as __________.

cohesion

__________ is the clinging of one substance to another, which helps transport water against gravity in plants.

Adhesion

__________ is a measure of how hard it is to break the surface of a liquid and is related to cohesion.

Surface tension

__________ represents the average kinetic energy of molecules, while __________ is a measure of the total amount of kinetic energy due to molecular motion.

Temperature; thermal energy

A __________ is the amount of heat required to raise the temperature of $1\,g$ of water by $1^\circ\text{C}$.

calorie (cal)

The relationship between Joules and calories is expressed as $1\,cal = 4.184\,J$ or $1\,J = 0.239\,cal$.

0.239 cal

The __________ of a substance is the amount of heat that must be absorbed or lost for $1\,g$ of that substance to change its temperature by $1^\circ\text{C}$.

specific heat

In water's hydrogen bonding, heat is __________ when hydrogen bonds break and heat is __________ when hydrogen bonds form.

absorbed; released

__________ is the transformation of a substance from liquid to gas.

Evaporation (vaporization)

Water reaches its greatest density at a temperature of __________.

$$4^\circ\text{C}$$

When an ionic compound is dissolved in water, each ion is surrounded by a sphere of water molecules called a __________.

hydration shell

A __________ substance has an affinity for water, while a __________ substance does not.

hydrophilic; hydrophobic

A __________ is a stable suspension of fine particles in a liquid.

colloid

__________ is the number of moles of solute per liter of solution.

Molarity (M)

When a hydrogen ion ($H^+$) binds to a water molecule, it forms a __________, which is represented by the formula $\text{H}_3\text{O}^+$.

hydronium ion

An __________ is a substance that increases the $H^+$ concentration of a solution, while a __________ reduces it.

acid; base

The pH of a solution is defined as the negative logarithm of the hydrogen ion concentration, written as __________.

pH = -\log[H^+]

Solutions with a pH less than $7$ are considered __________, and those with a pH greater than $7$ are considered __________.

acidic; basic

__________ are substances that minimize changes in concentrations of $H^+$ and $\text{OH}^-$ in a solution.

Buffers

Ocean acidification is a threat caused by human activities such as burning fossil fuels, which leads to the formation of __________ when $\text{CO}_2$ is absorbed by the oceans.

carbonic acid

It is predicted that carbonate ion concentrations in the ocean will decline by __________ by the year $2100$.

$$40\%$$