Lecture 1 Polarity, Water

Molecular (chemical) formulas

Formulas that give the number and types of atoms within a molecule.

Structural formulas

Formulas that give the number and types of atoms within a molecule, as well as their spatial arrangements.

Isomers

Molecules composed of the same number and types of elements, but arranged differently in space.

$$C_6H_{12}O_6$$

The common molecular formula shared by Glucose, Fructose, and Galactose.

Electronegativity

The attraction of an atom to electrons shared in covalent bonds, which affects how close it pulls the electrons towards its nucleus.

Non-Polar Covalent Bond

A bond formed when two atoms have the same electronegativity, resulting in electrons being shared equally and positioned at an equal distance between the two atomic nuclei.

Methane

A substance with the chemical formula $CH_4$.

Carbon Dioxide

A substance with the chemical formula $CO_2$ and the structural formula $O=C=O$.

Molecules composed of the same number and types of elements but arranged differently in space are called __________.

Isomers

__________ give the number and types of atoms within a molecule as well as their spatial arrangements.

Structural formulas

The attraction of an atom for electrons shared in covalent bonds is known as __________.

electronegativity

If two atoms share electrons equally because they have the same electronegativity, they form a(n) __________ covalent bond.

Nonpolar

In a water ($H_2O$) molecule, the oxygen atom takes on a slight __________ charge.

negative

Molecules like phospholipids that contain both polar and non-polar bonds are described as __________.

amphipathic

__________ are inter- and intra-molecular interactions that form between the slight positive charge of one polar molecule and the slight negative charge of another.

Hydrogen bonds

The inward pull of hydrogen bonds at the surface of water is called __________.

Surface tension

The body creates a(n) __________ to inhibit the collapsing of the lungs caused by surface tension.

surfactant

__________ is the amount of energy required to increase the temperature of $1\,gram$ of a substance in $Celsius$.

Specific heat

The amount of energy required to release molecules from a liquid phase to a gaseous one is the __________.

heat of vaporization

When ionic compounds like $NaCl$ dissolve and dissociate, the resulting ions are __________ as they are surrounded by water molecules.

hydrated

The process by which hydrogen bonds force nonpolar molecules together and out of water is called __________.

hydrophobic exclusion

A mixture composed of relatively large particles that does not stay mixed unless in motion, such as sand in water, is a(n) __________.

Suspension

A(n) __________ remains mixed when not in motion and can become gel-like when cooled, such as proteins in plasma.

Colloid

A(n) __________ occurs between water and nonpolar substances which only mix when agitated, such as breast milk.

Emulsion

Water molecules spontaneously dissociate to form a hydroxide ion ($OH^-$) and a(n) __________ ($H^+$).

hydrogen ion

A hydrogen ion binds with a water molecule to form __________, represented as $H_3O^+$.

hydronium

A substance that dissociates and releases a(n) $H^+$ in water is a(n) __________, also known as a proton donor.

acid

A(n) __________ is a substance that binds with free $H^+$ ions in a solution and is also called a proton acceptor.

base

The pH scale is __________ related to $H^+$ concentration, meaning as the pH value goes down, there are more $H^+$ in the solution.

inversely

The pH scale represents a(n) $-10$-fold change in $H^+$ concentration; for example, a solution with a pH of $6$ has __________ times more $H^+$ ions than a solution with a pH of $7$.

$$10$$

The __________ of a protein occurs when its shape is affected by pH extremes, rendering it useless.

denaturation

The body uses __________ to maintain a blood pH between $7.35$ and $7.45$.

buffers

In the blood buffer system, __________ ($H_2CO_3$) can donate a(n) $H^+$ to convert into bicarbonate ($HCO_3^-$).

Carbonic acid