Moles of Compounds

Front

Mole Noun

---

[mohl]

Back

Mole

---

The SI base unit for the amount of a substance, representing 6.022 × 10²³ representative particles of that substance.

---

Example: This image shows that one mole is a specific quantity (6.022 x 10^23 particles) and has a mass that can be measured, like 12 grams for carbon.

Front

Representative Particle Noun

---

[rep-ri-zen-tuh-tiv par-ti-kuhl]

Back

Representative Particle

---

The smallest unit in which a substance naturally exists, which can be an atom, a molecule, or a formula unit.

---

Example: For an ionic compound like salt, the representative particle is a 'formula unit,' which is the smallest whole-number ratio of ions in the crystal.

Front

Molar Mass Noun

---

[moh-ler mas]

Back

Molar Mass

---

The mass in grams of one mole of a pure substance, which is expressed in units of grams per mole (g/mol).

---

Example: The molar mass of a compound is calculated by adding the atomic masses of each atom in the molecule, as shown for water (H₂O).

Front

Chemical Formula Noun

---

[kem-i-kuhl for-myoo-luh]

Back

Chemical Formula

---

A representation of a compound indicating the types and numbers of atoms present in one unit of the substance.

---

Example: This image shows a model of a methane molecule and its chemical formula, CH₄, which indicates it contains one carbon (C) and four hydrogen (H) atoms.

Front

Subscript Noun

---

[suhb-skript]

Back

Subscript

---

A number in a chemical formula written slightly below and to the right of a symbol to show atom quantity.

---

Example: The subscript '2' in the chemical formula CO₂ indicates that there are two oxygen atoms for every one carbon atom in a molecule of carbon dioxide.

Front

Mole Ratio Noun

---

[mohl rey-shee-oh]

Back

Mole Ratio

---

A conversion factor from a formula's subscripts that relates the moles of elements within one mole of the compound.

---

Example: This image shows that for every two molecules of hydrogen (H₂) and one molecule of oxygen (O₂), two molecules of water (H₂O) are formed.

Front

Avogadro's Number Noun

---

[ah-vuh-gah-drohz nuhm-ber]

Back

Avogadro's Number

---

The number of representative particles in one mole of a substance, which is approximately 6.022 × 10²³ particles per mole.

---

Example: This image shows that Avogadro's number (6.022 x 10^23) is the quantity of atoms found in exactly 12 grams of carbon.

Front

Formula Unit Noun

---

[for-myoo-luh yoo-nit]

Back

Formula Unit

---

The simplest whole-number ratio of ions in an ionic compound, which serves as its representative particle.

---

Example: The image shows one sodium ion (Na+) and one chloride ion (Cl-), representing the 1:1 ratio that makes up one formula unit of sodium chloride.

Front

Ionic Compound Noun

---

[ahy-on-ik kom-pound]

Back

Ionic Compound

---

A chemical compound composed of positive and negative ions held together by electrostatic forces, typically formed from metals and nonmetals.

---

Example: A sodium (Na) atom gives one electron to a chlorine (Cl) atom, forming charged ions (Na+ and Cl-) that attract each other, creating an ionic compound.

Front

Molecular Compound Noun

---

[muh-lek-yuh-ler kom-pound]

Back

Molecular Compound

---

A chemical compound whose simplest units are molecules, formed when two or more nonmetal atoms share electrons via covalent bonds.

---

Example: This image shows a water molecule, a classic example of a molecular compound, where nonmetal atoms (two Hydrogen and one Oxygen) are joined by chemical bonds.